{"gene":"PRM1","run_date":"2026-04-28T19:45:45","timeline":{"discoveries":[{"year":2007,"finding":"The histone H3K9me2/1-specific demethylase JHDM2A (JMJD1A) directly binds to and controls transcription of the Prm1 gene; Jhdm2a-deficient mice exhibit post-meiotic chromatin condensation defects with loss of Prm1 expression, establishing JHDM2A as a direct upstream transcriptional regulator of Prm1.","method":"ChIP assay (direct binding to Prm1 locus), loss-of-function knockout mice with chromatin condensation phenotype","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 — reciprocal ChIP + in vivo KO with defined cellular phenotype, single lab but orthogonal methods","pmids":["17943087"],"is_preprint":false},{"year":1990,"finding":"Human PRM1 gene contains a single intron (91 bp), TATAA and CAAT boxes at conventional distances, and is clustered with PRM2 at a distance of 4.8 kb on chromosome 16p13; the 5'-noncoding region shares 12 motifs with PRM2 that may reflect regulatory elements for testis- and spermatid-specific expression.","method":"Cosmid library cloning, primer extension, Southern blotting, sequence analysis","journal":"Genomics","confidence":"High","confidence_rationale":"Tier 1 — direct genomic sequencing and structural characterization with functional annotation, foundational paper","pmids":["2081589"],"is_preprint":false},{"year":1994,"finding":"Germ cell-specific proteins bind the 3' UTR of Prm1 mRNA within meiotic spermatocytes and postmeiotic round spermatids; the binding site maps to a 22-nt region of the Prm1 3' UTR and forms two RNA/protein complexes (53 and 55 kDa), consistent with a role in translational repression of stored Prm1 mRNA.","method":"RNA band shift assay, UV cross-linking, deletion mapping of 3' UTR, cell fractionation","journal":"Developmental biology","confidence":"High","confidence_rationale":"Tier 1-2 — in vitro RNA-binding assay with deletion mapping, UV cross-linking, and cell-type-specific fractionation","pmids":["7813783"],"is_preprint":false},{"year":1995,"finding":"PRM1, PRM2, and TNP2 transcripts are expressed post-meiotically and are restricted to round and elongating spermatids in human seminiferous epithelium; they are absent from spermatogonia, spermatocytes, Sertoli cells, and interstitial cells, establishing their cell-type-specific expression pattern.","method":"In situ hybridization with [α-35S]-labeled cRNA probes on human testis sections","journal":"DNA and cell biology","confidence":"High","confidence_rationale":"Tier 2 — direct localization by ISH with cell-type resolution","pmids":["7865133"],"is_preprint":false},{"year":2016,"finding":"Sperm lacking Prm1 (Prm1-/- sperm) display abnormal shape, destabilized DNA, decondensed chromatin, and reduced mitochondrial membrane potential; zona-free oocyte ICSI revealed these sperm can nonetheless support viable offspring, demonstrating Prm1's role in chromatin condensation and sperm structural integrity but showing it is not strictly required for fertilization competence.","method":"CRISPR/gene targeting to generate Prm1-null mice, ICSI with zona-free oocytes, chromatin/DNA integrity assays","journal":"Scientific reports","confidence":"High","confidence_rationale":"Tier 2 — clean KO with defined structural and functional phenotype, multiple assays","pmids":["27250771"],"is_preprint":false},{"year":2022,"finding":"CRISPR-Cas9-generated Prm1-deficient mice showed that Prm1 is required for proper PRM2 processing to mature PRM2; Prm1+/- sperm had high levels of incompletely processed PRM2, a skewed PRM1:PRM2 ratio (1:5 instead of 1:2), protamine-deficient chromatin, elevated reactive oxygen species-mediated DNA damage, and reduced sperm motility, establishing PRM1's role in controlling the PRM1:PRM2 ratio and chromatin hypercondensation.","method":"CRISPR-Cas9 KO mice, CMA3 staining, ROS assay, western blotting for PRM2 processing, sperm motility analysis, DNA damage assays","journal":"Development (Cambridge, England)","confidence":"High","confidence_rationale":"Tier 2 — clean KO with multiple orthogonal phenotypic assays establishing molecular mechanism","pmids":["35608054"],"is_preprint":false},{"year":2010,"finding":"Overexpression of Prm1-EGFP fusion protein in elongating spermatids causes dominant male sterility in transgenic mice due to impaired spermatid maturation affecting sperm viability and motility; high Prm1-EGFP levels in sperm also failed to support preimplantation embryonic development after ICSI.","method":"Transgenic mouse overexpression under Prm1 transcriptional/translational control, sperm viability and motility assays, ICSI embryo development","journal":"Genesis (New York, N.Y. : 2000)","confidence":"Medium","confidence_rationale":"Tier 2 — gain-of-function in vivo with defined phenotype, single lab","pmids":["20095053"],"is_preprint":false},{"year":2001,"finding":"The PRM1→PRM2→TNP2 multigenic domain specifically localizes to the sperm nuclear matrix, and this association is independent of Alu methylation status, establishing that nuclear matrix attachment organizes this locus as a discrete chromatin domain in sperm.","method":"Fluorescence in situ hybridization on sperm nuclear matrix/halo preparations, methylation analysis of Alu elements","journal":"Molecular human reproduction","confidence":"Medium","confidence_rationale":"Tier 2 — direct FISH-based localization with mechanistic dissection of Alu methylation independence","pmids":["11574659"],"is_preprint":false},{"year":1998,"finding":"Electron microscopic in situ hybridization showed that PRM1 transcripts accumulate in the cytoplasm of round spermatids without compartmentalization and disappear at the end of the elongation phase coinciding with protamine deposition, consistent with translational delay/repression followed by release during spermatid elongation.","method":"Double EM in situ hybridization with digoxigenin/biotin probes and colloidal gold immunodetection on human spermatids","journal":"Italian journal of anatomy and embryology","confidence":"Medium","confidence_rationale":"Tier 2 — direct EM-level subcellular localization with stage-specific temporal correlation","pmids":["11315969"],"is_preprint":false},{"year":2025,"finding":"Overexpression of PRM1 in somatic cells (HEK293T and MSCs) causes nuclear condensation with notable PRM1 enrichment in nucleoli, reduces specific histone modifications (H3K9me3, H3K4me1, H3K27Ac), and significantly diminishes transcription especially of ribosomal genes, without altering DNA methylation; PRM1 and PRM2 condense distinct genomic regions.","method":"PRM1 overexpression in HEK293T and MSC cells, immunofluorescence for histone modifications, transcriptomics, WGBS methylome analysis","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal methods in preprint, not yet peer-reviewed","pmids":[],"is_preprint":true},{"year":2025,"finding":"Mutation of PRM1 Cys15 and Cys29 (identified as species-specific cysteine residues) in mice disrupted sperm chromatin condensation and increased histone retention, while sperm count and protamine expression levels remained unchanged; forced expression of mouse vs. human PRM1 in fibroblasts produced different nuclear shapes, establishing that PRM1 cysteine residue positions determine species-specific nuclear sperm shape and histone retention.","method":"CRISPR-generated knock-in mice with Cys15/Cys29 mutations, transmission electron microscopy of sperm chromatin, forced expression of PRM1 in fibroblasts, histone retention assays","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1-2 — mutagenesis + TEM + in vivo mouse model in preprint, not yet peer-reviewed","pmids":[],"is_preprint":true},{"year":2024,"finding":"Expression of Prm1 (sperm-specific protein) in somatic cells drives the genome towards the nuclear periphery with a 3-5 fold reduction in nuclear volume occupied by DNA, and Hi-C analysis showed that chromatin interaction patterns are largely robust to this reorganization with minor strengthening of heterochromatin self-interactions.","method":"Prm1 expression in somatic cells, microscopy, Hi-C chromatin interaction mapping","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 — preprint, single lab, mechanistic follow-up is limited to correlation between Prm1 expression and nuclear reorganization","pmids":[],"is_preprint":true}],"current_model":"PRM1 (Protamine 1) is a small, arginine-rich spermatid-expressed protein that replaces histones during chromatin hypercondensation in late spermiogenesis; its transcription is directly regulated by the histone demethylase JHDM2A (H3K9me2/1), its mRNA is translationally repressed in round spermatids via germ cell-specific proteins binding a 22-nt element in its 3' UTR, its protein is required for proper processing and maintenance of the correct PRM1:PRM2 ratio (critical for chromatin compaction and sperm fertility), its specific cysteine residues (Cys15, Cys29 in mice) determine sperm nuclear shape and histone retention, and the PRM1→PRM2→TNP2 locus is organized as a discrete nuclear matrix-attached chromatin domain in sperm."},"narrative":{"teleology":[{"year":1990,"claim":"Defining the genomic architecture of PRM1 — its single-intron structure, conserved promoter elements, and tight physical linkage with PRM2 on chromosome 16p13 — established the foundation for understanding coordinated spermatid-specific transcriptional regulation.","evidence":"Cosmid cloning, primer extension, Southern blotting, and sequence analysis of the human PRM1 locus","pmids":["2081589"],"confidence":"High","gaps":["Functional significance of the 12 shared 5′ motifs with PRM2 was not tested","No demonstration that physical linkage is required for co-regulation"]},{"year":1994,"claim":"Identification of germ-cell-specific RNA-binding proteins that recognize a 22-nt element in the PRM1 3′ UTR resolved how PRM1 mRNA is stored in round spermatids and translationally repressed until elongation.","evidence":"RNA band-shift assay, UV cross-linking, and deletion mapping using fractionated spermatocyte and spermatid extracts","pmids":["7813783"],"confidence":"High","gaps":["Identity of the 53- and 55-kDa binding proteins was not determined","Mechanism of translational derepression at elongation was not addressed"]},{"year":1995,"claim":"In situ hybridization on human testis demonstrated that PRM1 transcripts are confined to round and elongating spermatids, excluding all other testicular cell types, establishing its strict post-meiotic expression pattern.","evidence":"In situ hybridization with radiolabeled cRNA probes on human seminiferous tubule sections","pmids":["7865133"],"confidence":"High","gaps":["Transcriptional vs. post-transcriptional basis for cell-type restriction was not distinguished"]},{"year":1998,"claim":"Ultrastructural visualization of PRM1 mRNA in round spermatids confirmed cytoplasmic accumulation without compartmentalization and disappearance during elongation coincident with protamine deposition, supporting the translational delay model.","evidence":"Double electron microscopic in situ hybridization with colloidal gold immunodetection on human spermatids","pmids":["11315969"],"confidence":"Medium","gaps":["Temporal resolution did not distinguish active translation from mRNA degradation","Correlation between mRNA disappearance and protein deposition was not causally tested"]},{"year":2001,"claim":"Demonstration that the PRM1→PRM2→TNP2 locus associates with the sperm nuclear matrix independently of Alu methylation revealed a higher-order chromatin domain organization that may facilitate coordinated packaging of the protamine gene cluster.","evidence":"FISH on sperm nuclear matrix/halo preparations combined with Alu methylation analysis","pmids":["11574659"],"confidence":"Medium","gaps":["Functional consequence of nuclear matrix attachment was not tested","Whether matrix attachment exists in spermatid precursors was not examined"]},{"year":2007,"claim":"Discovery that the H3K9me2/me1 demethylase JHDM2A directly binds the Prm1 promoter and is required for its transcription linked epigenetic chromatin remodeling to protamine gene activation, explaining how the histone-to-protamine transition is initiated.","evidence":"ChIP showing JHDM2A occupancy at the Prm1 locus; Jhdm2a-knockout mice with loss of Prm1 expression and chromatin condensation defects","pmids":["17943087"],"confidence":"High","gaps":["Whether JHDM2A is sufficient or additional cofactors are needed was not resolved","Downstream signaling between H3K9 demethylation and transcriptional activation at Prm1 was not dissected"]},{"year":2010,"claim":"Overexpression of a PRM1-EGFP fusion in elongating spermatids caused dominant male sterility through impaired spermatid maturation, demonstrating that protamine dosage is critical and excess PRM1 is as detrimental as its absence.","evidence":"Transgenic mice expressing Prm1-EGFP under Prm1 regulatory elements; sperm viability, motility, and ICSI embryo development assays","pmids":["20095053"],"confidence":"Medium","gaps":["Whether the EGFP tag itself contributed to toxicity was not fully controlled","Molecular mechanism of dominant toxicity was not identified"]},{"year":2016,"claim":"Complete Prm1 knockout established that PRM1 is essential for normal chromatin condensation, sperm shape, and DNA stability, yet Prm1-null sperm can support offspring via ICSI, separating chromatin packaging from minimal fertilization competence.","evidence":"CRISPR-generated Prm1-null mice with chromatin integrity and mitochondrial membrane potential assays; zona-free ICSI","pmids":["27250771"],"confidence":"High","gaps":["Long-term developmental consequences in ICSI-derived offspring were not assessed","Whether residual PRM2 partially compensates was not tested"]},{"year":2022,"claim":"Detailed phenotyping of Prm1+/− and Prm1−/− mice revealed that PRM1 is required for proper PRM2 processing to its mature form; haploinsufficiency skews the PRM1:PRM2 ratio from ~1:2 to ~1:5, causing protamine-deficient chromatin, ROS-mediated DNA damage, and reduced motility.","evidence":"CRISPR-Cas9 knockout mice with CMA3 staining, western blotting for PRM2 processing intermediates, ROS and DNA damage assays, motility analysis","pmids":["35608054"],"confidence":"High","gaps":["Mechanism by which PRM1 promotes PRM2 processing is unknown","Whether haploinsufficiency phenotype is universal across genetic backgrounds was not tested"]},{"year":null,"claim":"Key unresolved questions include the molecular mechanism by which PRM1 facilitates PRM2 processing, the identity of the 3′ UTR-binding proteins that mediate translational repression, and the structural basis of PRM1-DNA interaction that drives species-specific chromatin compaction.","evidence":"","pmids":[],"confidence":"High","gaps":["Identity of PRM1 3′ UTR translational repressor proteins remains unknown","No structural model of PRM1-DNA or PRM1-PRM2 interaction exists","Mechanism linking PRM1 cysteine residues to histone eviction and nuclear shaping is not established"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0003677","term_label":"DNA binding","supporting_discovery_ids":[4,5,9]}],"localization":[{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[3,4,5,8]},{"term_id":"GO:0005694","term_label":"chromosome","supporting_discovery_ids":[4,5,7]}],"pathway":[{"term_id":"R-HSA-1474165","term_label":"Reproduction","supporting_discovery_ids":[3,4,5]},{"term_id":"R-HSA-4839726","term_label":"Chromatin organization","supporting_discovery_ids":[0,4,5]}],"complexes":[],"partners":["JHDM2A","PRM2","TNP2"],"other_free_text":[]},"mechanistic_narrative":"PRM1 (Protamine 1) is a small, arginine-rich nuclear protein that replaces histones during spermiogenesis to drive chromatin hypercondensation, thereby establishing sperm nuclear architecture and DNA stability. PRM1 is transcribed exclusively in post-meiotic round and elongating spermatids under direct control of the H3K9 demethylase JHDM2A, and its mRNA is translationally repressed via germ-cell-specific proteins binding a 22-nucleotide element in the 3′ UTR until the elongation phase [PMID:17943087, PMID:7813783, PMID:7865133]. Loss of PRM1 results in decondensed chromatin, abnormal sperm morphology, elevated reactive oxygen species–mediated DNA damage, and disrupted processing of PRM2 to its mature form, skewing the PRM1:PRM2 ratio critical for chromatin compaction and male fertility [PMID:27250771, PMID:35608054]. Specific cysteine residues within PRM1 determine species-specific sperm nuclear shape and histone retention, and the PRM1→PRM2→TNP2 locus is organized as a nuclear matrix–attached chromatin domain in sperm [PMID:11574659]."},"prefetch_data":{"uniprot":{"accession":"P04553","full_name":"Sperm protamine P1","aliases":["Cysteine-rich protamine"],"length_aa":51,"mass_kda":6.8,"function":"Protamines substitute for histones in the chromatin of sperm during the haploid phase of spermatogenesis. They compact sperm DNA into a highly condensed, stable and inactive complex","subcellular_location":"Nucleus; Chromosome","url":"https://www.uniprot.org/uniprotkb/P04553/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/PRM1","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/PRM1","total_profiled":1310},"omim":[{"mim_id":"620881","title":"COILED-COIL GLUTAMATE-RICH PROTEIN 1; CCER1","url":"https://www.omim.org/entry/620881"},{"mim_id":"614130","title":"ADENOSINE DEAMINASE DOMAIN-CONTAINING PROTEIN 1, TESTIS-SPECIFIC; ADAD1","url":"https://www.omim.org/entry/614130"},{"mim_id":"613822","title":"PROTEIN PHOSPHATASE 4, REGULATORY SUBUNIT 2; PPP4R2","url":"https://www.omim.org/entry/613822"},{"mim_id":"612758","title":"TRANSMEMBRANE ANTERIOR POSTERIOR TRANSFORMATION 1; TAPT1","url":"https://www.omim.org/entry/612758"},{"mim_id":"611512","title":"LYSINE DEMETHYLASE 3A; KDM3A","url":"https://www.omim.org/entry/611512"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Nucleoplasm","reliability":"Enhanced"},{"location":"Cytosol","reliability":"Enhanced"}],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"testis","ntpm":15140.1}],"url":"https://www.proteinatlas.org/search/PRM1"},"hgnc":{"alias_symbol":["CT94.1"],"prev_symbol":[]},"alphafold":{"accession":"P04553","domains":[],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P04553","model_url":"https://alphafold.ebi.ac.uk/files/AF-P04553-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P04553-F1-predicted_aligned_error_v6.png","plddt_mean":54.12},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=PRM1","jax_strain_url":"https://www.jax.org/strain/search?query=PRM1"},"sequence":{"accession":"P04553","fasta_url":"https://rest.uniprot.org/uniprotkb/P04553.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P04553/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P04553"}},"corpus_meta":[{"pmid":"17943087","id":"PMC_17943087","title":"Histone demethylase JHDM2A is critical for Tnp1 and Prm1 transcription and spermatogenesis.","date":"2007","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/17943087","citation_count":311,"is_preprint":false},{"pmid":"2081589","id":"PMC_2081589","title":"Genomic sequences of human protamines whose genes, PRM1 and PRM2, are clustered.","date":"1990","source":"Genomics","url":"https://pubmed.ncbi.nlm.nih.gov/2081589","citation_count":91,"is_preprint":false},{"pmid":"17151357","id":"PMC_17151357","title":"The plasma membrane proteins Prm1 and Fig1 ascertain fidelity of membrane fusion during yeast mating.","date":"2006","source":"Molecular biology of the cell","url":"https://pubmed.ncbi.nlm.nih.gov/17151357","citation_count":71,"is_preprint":false},{"pmid":"2882955","id":"PMC_2882955","title":"Genetic mapping of Prm-1, Igl-1, Smst, Mtv-6, Sod-1, and Ets-2 and localization of the Down syndrome region on mouse chromosome 16.","date":"1987","source":"Cytogenetics and cell 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(PRM1).","date":"1991","source":"Cytogenetics and cell genetics","url":"https://pubmed.ncbi.nlm.nih.gov/1906796","citation_count":22,"is_preprint":false},{"pmid":"9723181","id":"PMC_9723181","title":"Extended analysis of the region encompassing the PRM1-->PRM2-->TNP2 domain: genomic organization, evolution and gene identification.","date":"1998","source":"The Journal of experimental zoology","url":"https://pubmed.ncbi.nlm.nih.gov/9723181","citation_count":19,"is_preprint":false},{"pmid":"11574659","id":"PMC_11574659","title":"Sperm nuclear matrix association of the PRM1-->PRM2-->TNP2 domain is independent of Alu methylation.","date":"2001","source":"Molecular human reproduction","url":"https://pubmed.ncbi.nlm.nih.gov/11574659","citation_count":17,"is_preprint":false},{"pmid":"25246894","id":"PMC_25246894","title":"Association study of six SNPs in PRM1, PRM2 and TNP2 genes in iranian infertile men with idiopathic azoospermia.","date":"2012","source":"Iranian journal of reproductive 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infections","url":"https://pubmed.ncbi.nlm.nih.gov/37526401","citation_count":5,"is_preprint":false},{"pmid":"30644249","id":"PMC_30644249","title":"Analysis of PRM1 and PRM2 Polymorphisms in Iranian Infertile Men with Idiopathic Teratozoospermia.","date":"2019","source":"International journal of fertility & sterility","url":"https://pubmed.ncbi.nlm.nih.gov/30644249","citation_count":5,"is_preprint":false},{"pmid":"36197138","id":"PMC_36197138","title":"Correlation of Single Nucleotide Polymorphisms of PRM1, PRM2, PYGO2, and DAZL Genes with Male Infertility in North West of Iran.","date":"2022","source":"Turkish journal of urology","url":"https://pubmed.ncbi.nlm.nih.gov/36197138","citation_count":4,"is_preprint":false},{"pmid":"28986257","id":"PMC_28986257","title":"Ecm22 and Upc2 regulate yeast mating through control of expression of the mating genes PRM1 and PRM4.","date":"2017","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/28986257","citation_count":4,"is_preprint":false},{"pmid":"38660591","id":"PMC_38660591","title":"CircANXA4 (hsa_circ_0055087) regulates the miR-1256/PRM1 axis to promote tumor progression in colorectal cancer.","date":"2024","source":"Non-coding RNA research","url":"https://pubmed.ncbi.nlm.nih.gov/38660591","citation_count":1,"is_preprint":false},{"pmid":"11315969","id":"PMC_11315969","title":"Electron microscopic in situ hybridization study of simultaneous expression of TNP1 and PRM1 genes in human spermatids.","date":"1998","source":"Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia","url":"https://pubmed.ncbi.nlm.nih.gov/11315969","citation_count":1,"is_preprint":false},{"pmid":"40934633","id":"PMC_40934633","title":"PRM1 modulates proliferation, apoptosis, and testosterone synthesis in bovine Leydig cells.","date":"2025","source":"Animal reproduction science","url":"https://pubmed.ncbi.nlm.nih.gov/40934633","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.09.26.678705","title":"Genomic and Epigenetic Interplay Drives Adaptive Fusion via Reproduction Trade-Off","date":"2025-09-27","source":"bioRxiv","url":"https://doi.org/10.1101/2025.09.26.678705","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.06.02.657337","title":"Protamine expression in somatic cells condenses chromatin and disrupts transcription without altering DNA methylation","date":"2025-06-03","source":"bioRxiv","url":"https://doi.org/10.1101/2025.06.02.657337","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.03.20.644273","title":"Protamine sequence determines species-specific nuclear shape and histone retention","date":"2025-03-22","source":"bioRxiv","url":"https://doi.org/10.1101/2025.03.20.644273","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.08.22.609170","title":"Large-scale manipulation of radial positioning does not affect most aspects of genome organization","date":"2024-08-23","source":"bioRxiv","url":"https://doi.org/10.1101/2024.08.22.609170","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.08.11.606797","title":"An aberrant protamine ratio is associated with decreased H4ac levels in murine and human sperm","date":"2024-08-11","source":"bioRxiv","url":"https://doi.org/10.1101/2024.08.11.606797","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":22784,"output_tokens":2942,"usd":0.056241},"stage2":{"model":"claude-opus-4-6","input_tokens":6282,"output_tokens":2378,"usd":0.13629},"total_usd":0.192531,"stage1_batch_id":"msgbatch_01SUR8NDzVrNmyszWyJeCct7","stage2_batch_id":"msgbatch_01G7Yfutko3cDWzejrwH5AMx","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2007,\n      \"finding\": \"The histone H3K9me2/1-specific demethylase JHDM2A (JMJD1A) directly binds to and controls transcription of the Prm1 gene; Jhdm2a-deficient mice exhibit post-meiotic chromatin condensation defects with loss of Prm1 expression, establishing JHDM2A as a direct upstream transcriptional regulator of Prm1.\",\n      \"method\": \"ChIP assay (direct binding to Prm1 locus), loss-of-function knockout mice with chromatin condensation phenotype\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal ChIP + in vivo KO with defined cellular phenotype, single lab but orthogonal methods\",\n      \"pmids\": [\"17943087\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Human PRM1 gene contains a single intron (91 bp), TATAA and CAAT boxes at conventional distances, and is clustered with PRM2 at a distance of 4.8 kb on chromosome 16p13; the 5'-noncoding region shares 12 motifs with PRM2 that may reflect regulatory elements for testis- and spermatid-specific expression.\",\n      \"method\": \"Cosmid library cloning, primer extension, Southern blotting, sequence analysis\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct genomic sequencing and structural characterization with functional annotation, foundational paper\",\n      \"pmids\": [\"2081589\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"Germ cell-specific proteins bind the 3' UTR of Prm1 mRNA within meiotic spermatocytes and postmeiotic round spermatids; the binding site maps to a 22-nt region of the Prm1 3' UTR and forms two RNA/protein complexes (53 and 55 kDa), consistent with a role in translational repression of stored Prm1 mRNA.\",\n      \"method\": \"RNA band shift assay, UV cross-linking, deletion mapping of 3' UTR, cell fractionation\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vitro RNA-binding assay with deletion mapping, UV cross-linking, and cell-type-specific fractionation\",\n      \"pmids\": [\"7813783\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"PRM1, PRM2, and TNP2 transcripts are expressed post-meiotically and are restricted to round and elongating spermatids in human seminiferous epithelium; they are absent from spermatogonia, spermatocytes, Sertoli cells, and interstitial cells, establishing their cell-type-specific expression pattern.\",\n      \"method\": \"In situ hybridization with [α-35S]-labeled cRNA probes on human testis sections\",\n      \"journal\": \"DNA and cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct localization by ISH with cell-type resolution\",\n      \"pmids\": [\"7865133\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Sperm lacking Prm1 (Prm1-/- sperm) display abnormal shape, destabilized DNA, decondensed chromatin, and reduced mitochondrial membrane potential; zona-free oocyte ICSI revealed these sperm can nonetheless support viable offspring, demonstrating Prm1's role in chromatin condensation and sperm structural integrity but showing it is not strictly required for fertilization competence.\",\n      \"method\": \"CRISPR/gene targeting to generate Prm1-null mice, ICSI with zona-free oocytes, chromatin/DNA integrity assays\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with defined structural and functional phenotype, multiple assays\",\n      \"pmids\": [\"27250771\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"CRISPR-Cas9-generated Prm1-deficient mice showed that Prm1 is required for proper PRM2 processing to mature PRM2; Prm1+/- sperm had high levels of incompletely processed PRM2, a skewed PRM1:PRM2 ratio (1:5 instead of 1:2), protamine-deficient chromatin, elevated reactive oxygen species-mediated DNA damage, and reduced sperm motility, establishing PRM1's role in controlling the PRM1:PRM2 ratio and chromatin hypercondensation.\",\n      \"method\": \"CRISPR-Cas9 KO mice, CMA3 staining, ROS assay, western blotting for PRM2 processing, sperm motility analysis, DNA damage assays\",\n      \"journal\": \"Development (Cambridge, England)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with multiple orthogonal phenotypic assays establishing molecular mechanism\",\n      \"pmids\": [\"35608054\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Overexpression of Prm1-EGFP fusion protein in elongating spermatids causes dominant male sterility in transgenic mice due to impaired spermatid maturation affecting sperm viability and motility; high Prm1-EGFP levels in sperm also failed to support preimplantation embryonic development after ICSI.\",\n      \"method\": \"Transgenic mouse overexpression under Prm1 transcriptional/translational control, sperm viability and motility assays, ICSI embryo development\",\n      \"journal\": \"Genesis (New York, N.Y. : 2000)\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain-of-function in vivo with defined phenotype, single lab\",\n      \"pmids\": [\"20095053\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The PRM1→PRM2→TNP2 multigenic domain specifically localizes to the sperm nuclear matrix, and this association is independent of Alu methylation status, establishing that nuclear matrix attachment organizes this locus as a discrete chromatin domain in sperm.\",\n      \"method\": \"Fluorescence in situ hybridization on sperm nuclear matrix/halo preparations, methylation analysis of Alu elements\",\n      \"journal\": \"Molecular human reproduction\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct FISH-based localization with mechanistic dissection of Alu methylation independence\",\n      \"pmids\": [\"11574659\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Electron microscopic in situ hybridization showed that PRM1 transcripts accumulate in the cytoplasm of round spermatids without compartmentalization and disappear at the end of the elongation phase coinciding with protamine deposition, consistent with translational delay/repression followed by release during spermatid elongation.\",\n      \"method\": \"Double EM in situ hybridization with digoxigenin/biotin probes and colloidal gold immunodetection on human spermatids\",\n      \"journal\": \"Italian journal of anatomy and embryology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct EM-level subcellular localization with stage-specific temporal correlation\",\n      \"pmids\": [\"11315969\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Overexpression of PRM1 in somatic cells (HEK293T and MSCs) causes nuclear condensation with notable PRM1 enrichment in nucleoli, reduces specific histone modifications (H3K9me3, H3K4me1, H3K27Ac), and significantly diminishes transcription especially of ribosomal genes, without altering DNA methylation; PRM1 and PRM2 condense distinct genomic regions.\",\n      \"method\": \"PRM1 overexpression in HEK293T and MSC cells, immunofluorescence for histone modifications, transcriptomics, WGBS methylome analysis\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods in preprint, not yet peer-reviewed\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Mutation of PRM1 Cys15 and Cys29 (identified as species-specific cysteine residues) in mice disrupted sperm chromatin condensation and increased histone retention, while sperm count and protamine expression levels remained unchanged; forced expression of mouse vs. human PRM1 in fibroblasts produced different nuclear shapes, establishing that PRM1 cysteine residue positions determine species-specific nuclear sperm shape and histone retention.\",\n      \"method\": \"CRISPR-generated knock-in mice with Cys15/Cys29 mutations, transmission electron microscopy of sperm chromatin, forced expression of PRM1 in fibroblasts, histone retention assays\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 — mutagenesis + TEM + in vivo mouse model in preprint, not yet peer-reviewed\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Expression of Prm1 (sperm-specific protein) in somatic cells drives the genome towards the nuclear periphery with a 3-5 fold reduction in nuclear volume occupied by DNA, and Hi-C analysis showed that chromatin interaction patterns are largely robust to this reorganization with minor strengthening of heterochromatin self-interactions.\",\n      \"method\": \"Prm1 expression in somatic cells, microscopy, Hi-C chromatin interaction mapping\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — preprint, single lab, mechanistic follow-up is limited to correlation between Prm1 expression and nuclear reorganization\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    }\n  ],\n  \"current_model\": \"PRM1 (Protamine 1) is a small, arginine-rich spermatid-expressed protein that replaces histones during chromatin hypercondensation in late spermiogenesis; its transcription is directly regulated by the histone demethylase JHDM2A (H3K9me2/1), its mRNA is translationally repressed in round spermatids via germ cell-specific proteins binding a 22-nt element in its 3' UTR, its protein is required for proper processing and maintenance of the correct PRM1:PRM2 ratio (critical for chromatin compaction and sperm fertility), its specific cysteine residues (Cys15, Cys29 in mice) determine sperm nuclear shape and histone retention, and the PRM1→PRM2→TNP2 locus is organized as a discrete nuclear matrix-attached chromatin domain in sperm.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"PRM1 (Protamine 1) is a small, arginine-rich nuclear protein that replaces histones during spermiogenesis to drive chromatin hypercondensation, thereby establishing sperm nuclear architecture and DNA stability. PRM1 is transcribed exclusively in post-meiotic round and elongating spermatids under direct control of the H3K9 demethylase JHDM2A, and its mRNA is translationally repressed via germ-cell-specific proteins binding a 22-nucleotide element in the 3′ UTR until the elongation phase [PMID:17943087, PMID:7813783, PMID:7865133]. Loss of PRM1 results in decondensed chromatin, abnormal sperm morphology, elevated reactive oxygen species–mediated DNA damage, and disrupted processing of PRM2 to its mature form, skewing the PRM1:PRM2 ratio critical for chromatin compaction and male fertility [PMID:27250771, PMID:35608054]. Specific cysteine residues within PRM1 determine species-specific sperm nuclear shape and histone retention, and the PRM1→PRM2→TNP2 locus is organized as a nuclear matrix–attached chromatin domain in sperm [PMID:11574659].\",\n  \"teleology\": [\n    {\n      \"year\": 1990,\n      \"claim\": \"Defining the genomic architecture of PRM1 — its single-intron structure, conserved promoter elements, and tight physical linkage with PRM2 on chromosome 16p13 — established the foundation for understanding coordinated spermatid-specific transcriptional regulation.\",\n      \"evidence\": \"Cosmid cloning, primer extension, Southern blotting, and sequence analysis of the human PRM1 locus\",\n      \"pmids\": [\"2081589\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional significance of the 12 shared 5′ motifs with PRM2 was not tested\", \"No demonstration that physical linkage is required for co-regulation\"]\n    },\n    {\n      \"year\": 1994,\n      \"claim\": \"Identification of germ-cell-specific RNA-binding proteins that recognize a 22-nt element in the PRM1 3′ UTR resolved how PRM1 mRNA is stored in round spermatids and translationally repressed until elongation.\",\n      \"evidence\": \"RNA band-shift assay, UV cross-linking, and deletion mapping using fractionated spermatocyte and spermatid extracts\",\n      \"pmids\": [\"7813783\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the 53- and 55-kDa binding proteins was not determined\", \"Mechanism of translational derepression at elongation was not addressed\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"In situ hybridization on human testis demonstrated that PRM1 transcripts are confined to round and elongating spermatids, excluding all other testicular cell types, establishing its strict post-meiotic expression pattern.\",\n      \"evidence\": \"In situ hybridization with radiolabeled cRNA probes on human seminiferous tubule sections\",\n      \"pmids\": [\"7865133\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Transcriptional vs. post-transcriptional basis for cell-type restriction was not distinguished\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Ultrastructural visualization of PRM1 mRNA in round spermatids confirmed cytoplasmic accumulation without compartmentalization and disappearance during elongation coincident with protamine deposition, supporting the translational delay model.\",\n      \"evidence\": \"Double electron microscopic in situ hybridization with colloidal gold immunodetection on human spermatids\",\n      \"pmids\": [\"11315969\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Temporal resolution did not distinguish active translation from mRNA degradation\", \"Correlation between mRNA disappearance and protein deposition was not causally tested\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Demonstration that the PRM1→PRM2→TNP2 locus associates with the sperm nuclear matrix independently of Alu methylation revealed a higher-order chromatin domain organization that may facilitate coordinated packaging of the protamine gene cluster.\",\n      \"evidence\": \"FISH on sperm nuclear matrix/halo preparations combined with Alu methylation analysis\",\n      \"pmids\": [\"11574659\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of nuclear matrix attachment was not tested\", \"Whether matrix attachment exists in spermatid precursors was not examined\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Discovery that the H3K9me2/me1 demethylase JHDM2A directly binds the Prm1 promoter and is required for its transcription linked epigenetic chromatin remodeling to protamine gene activation, explaining how the histone-to-protamine transition is initiated.\",\n      \"evidence\": \"ChIP showing JHDM2A occupancy at the Prm1 locus; Jhdm2a-knockout mice with loss of Prm1 expression and chromatin condensation defects\",\n      \"pmids\": [\"17943087\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether JHDM2A is sufficient or additional cofactors are needed was not resolved\", \"Downstream signaling between H3K9 demethylation and transcriptional activation at Prm1 was not dissected\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Overexpression of a PRM1-EGFP fusion in elongating spermatids caused dominant male sterility through impaired spermatid maturation, demonstrating that protamine dosage is critical and excess PRM1 is as detrimental as its absence.\",\n      \"evidence\": \"Transgenic mice expressing Prm1-EGFP under Prm1 regulatory elements; sperm viability, motility, and ICSI embryo development assays\",\n      \"pmids\": [\"20095053\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether the EGFP tag itself contributed to toxicity was not fully controlled\", \"Molecular mechanism of dominant toxicity was not identified\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Complete Prm1 knockout established that PRM1 is essential for normal chromatin condensation, sperm shape, and DNA stability, yet Prm1-null sperm can support offspring via ICSI, separating chromatin packaging from minimal fertilization competence.\",\n      \"evidence\": \"CRISPR-generated Prm1-null mice with chromatin integrity and mitochondrial membrane potential assays; zona-free ICSI\",\n      \"pmids\": [\"27250771\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Long-term developmental consequences in ICSI-derived offspring were not assessed\", \"Whether residual PRM2 partially compensates was not tested\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Detailed phenotyping of Prm1+/− and Prm1−/− mice revealed that PRM1 is required for proper PRM2 processing to its mature form; haploinsufficiency skews the PRM1:PRM2 ratio from ~1:2 to ~1:5, causing protamine-deficient chromatin, ROS-mediated DNA damage, and reduced motility.\",\n      \"evidence\": \"CRISPR-Cas9 knockout mice with CMA3 staining, western blotting for PRM2 processing intermediates, ROS and DNA damage assays, motility analysis\",\n      \"pmids\": [\"35608054\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which PRM1 promotes PRM2 processing is unknown\", \"Whether haploinsufficiency phenotype is universal across genetic backgrounds was not tested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the molecular mechanism by which PRM1 facilitates PRM2 processing, the identity of the 3′ UTR-binding proteins that mediate translational repression, and the structural basis of PRM1-DNA interaction that drives species-specific chromatin compaction.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of PRM1 3′ UTR translational repressor proteins remains unknown\", \"No structural model of PRM1-DNA or PRM1-PRM2 interaction exists\", \"Mechanism linking PRM1 cysteine residues to histone eviction and nuclear shaping is not established\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0003677\", \"supporting_discovery_ids\": [4, 5, 9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [3, 4, 5, 8]},\n      {\"term_id\": \"GO:0005694\", \"supporting_discovery_ids\": [4, 5, 7]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1474165\", \"supporting_discovery_ids\": [3, 4, 5]},\n      {\"term_id\": \"R-HSA-4839726\", \"supporting_discovery_ids\": [0, 4, 5]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"JHDM2A\", \"PRM2\", \"TNP2\"],\n    \"other_free_text\": []\n  }\n}\n```"}