Affinage

MEI4

Meiosis-specific protein MEI4 · UniProt A8MW99

Length
385 aa
Mass
44.0 kDa
Annotated
2026-04-28
22 papers in source corpus 20 papers cited in narrative 20 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

MEI4 is an evolutionarily conserved component of the meiotic double-strand break (DSB) machinery that functions as an essential determinant of SPO11-dependent DSB formation during meiotic prophase. In budding yeast and mammals, MEI4 forms a 2:1 heterotrimeric complex with REC114 (two REC114 protomers cupping the MEI4 N-terminal α-helix), which cooperatively binds DNA and assembles into dynamic condensates capable of bridging DNA duplexes; this complex further associates with IHO1/Mer2 on meiotic chromosome axes in a manner dependent on HORMAD1, REC8, RAD21L, and MEI1, with axis-associated MEI4 levels acting as a quantitative limiting factor for DSB number (PMID:20551173, PMID:25795304, PMID:37442580, PMID:30569039, PMID:37431931). In the fission yeast S. pombe, a distinct Mei4 protein functions instead as a forkhead transcription factor that binds FLEX cis-elements to activate middle-phase meiotic genes and regulate meiotic nuclear dynamics (PMID:9528784, PMID:10747048). Bi-allelic missense or truncation variants in human MEI4 cause female infertility through impaired DSB formation and oocyte apoptosis (PMID:38252283, PMID:41419020).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 1989 High

    The first mechanistic placement of MEI4 in the meiotic recombination pathway established that it acts upstream of RAD52, positioning it as a factor required early in recombination initiation rather than during strand exchange or repair.

    Evidence Genetic epistasis analysis using mei4, rad52, and spo13 double/triple mutants in S. cerevisiae

    PMID:2693205

    Open questions at the time
    • Molecular function of MEI4 protein unknown
    • No distinction yet between DSB formation vs. processing roles
  2. 1992 High

    Cytological analysis revealed that MEI4 is required for synaptonemal complex formation but not for axial element assembly, narrowing its function to a step between axis formation and synapsis — later understood to be DSB initiation.

    Evidence Cytological analysis of meiotic chromosome structures and Northern blot in S. cerevisiae mei4 mutants

    PMID:1545815

    Open questions at the time
    • Whether the synapsis defect is secondary to a DSB defect was not tested
    • Protein localization not determined
  3. 1998 High

    The discovery that S. pombe Mei4 is a forkhead transcription factor that binds GTAAAYA sequences and activates meiotic genes established that the name 'Mei4' covers functionally distinct proteins in different organisms — a transcription factor in fission yeast versus a DSB machinery component in budding yeast and mammals.

    Evidence EMSA, one-hybrid assay, and promoter deletion analysis of S. pombe mei4 and spo6

    PMID:10747048 PMID:9528784

    Open questions at the time
    • Relationship between S. pombe Mei4 and its DSB ortholog (Rec24) not yet clarified
    • Full set of transcriptional targets unknown at this point
  4. 2006 High

    Identification of the Mei4–Rec114–Mer2 complex in S. cerevisiae provided the first evidence that these three proteins form a discrete subcomplex within the DSB machinery, distinct from the Spo11 catalytic core.

    Evidence Reciprocal co-immunoprecipitation and cytological colocalization on meiotic chromosome spreads

    PMID:16783010 PMID:17558514

    Open questions at the time
    • Stoichiometry of the complex unknown
    • How the subcomplex communicates with Spo11 not established
  5. 2010 High

    Generation of Mei4−/− knockout mice demonstrated that the DSB-promoting role of MEI4 is conserved in mammals; axis localization of MEI4 and its direct interaction with REC114 through conserved motifs established the mammalian MEI4-REC114 module.

    Evidence Mouse knockout phenotyping, immunofluorescence on meiotic spreads, and direct protein interaction assays with mutagenesis

    PMID:20551173

    Open questions at the time
    • Structural basis of MEI4-REC114 interaction unresolved
    • How MEI4 is recruited to axes unknown
  6. 2015 High

    Quantitative cytological analysis across multiple mouse mutants revealed that MEI4 axis loading depends on HORMAD1, MEI1, REC8, and RAD21L, and that axis-associated MEI4 levels quantitatively limit DSB numbers — establishing MEI4 as a regulatory node for DSB control.

    Evidence Immunofluorescence in Hormad1, Mei1, Rec8, and Rad21l knockout mice with quantitative correlation of MEI4 foci and DSB markers

    PMID:25795304

    Open questions at the time
    • Whether MEI4 dosage directly or indirectly limits DSBs not distinguished
    • Post-translational regulation of MEI4 not explored
  7. 2018 High

    Biochemical reconstitution and structural analysis of the REC114-MEI4 complex defined the interaction interface (REC114 C-terminus to MEI4 N-terminus), revealed the REC114 PH-like domain, and confirmed colocalization with IHO1 on axes, establishing the architecture of the mammalian pre-DSB complex.

    Evidence In vitro reconstitution, crystal structure of REC114 N-terminal domain, cytological co-localization in mouse spermatocytes

    PMID:30569039

    Open questions at the time
    • Full complex stoichiometry with IHO1 not determined
    • No in vitro DSB formation assay available
  8. 2023 High

    Structural and biophysical studies resolved the 2:1 REC114-MEI4 heterotrimer architecture by NMR and AlphaFold2, demonstrated that this complex cooperatively binds DNA and forms dynamic condensates that bridge DNA duplexes, providing a physical mechanism for how the pre-DSB machinery organizes chromatin for SPO11 access.

    Evidence NMR spectroscopy, SEC-MALS, ITC, single-molecule assays, AlphaFold2 modeling with mutagenesis validation across yeast and mouse systems

    PMID:37431931 PMID:37442580 PMID:37442581

    Open questions at the time
    • How condensate formation is regulated in vivo not established
    • Whether DNA bridging is required for DSB formation in vivo not tested
    • Relationship between REC114-MEI4 condensates and Mer2 condensates in vivo unclear
  9. 2024 Medium

    Human genetic studies linked bi-allelic MEI4 missense variants to female infertility via preimplantation embryonic arrest, with knock-in mouse models recapitulating oogenesis defects, establishing MEI4 as a human disease gene.

    Evidence Patient variant identification; in vitro DNA-interaction assays with mutant protein; knock-in mouse model with oogenesis phenotype analysis

    PMID:38252283 PMID:41419020

    Open questions at the time
    • Number of families studied is limited
    • Male fertility effects of these specific variants not fully characterized
    • Genotype-phenotype correlation across variant types not established

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include how MEI4-REC114-IHO1 condensate dynamics are regulated to achieve proper DSB timing and distribution in vivo, how the complex communicates with SPO11 to trigger catalysis, and whether MEI4 has functions beyond DSB initiation.
  • No reconstituted in vitro DSB formation system exists
  • Post-translational modifications regulating MEI4 axis dynamics are uncharacterized
  • Structural basis of the full REC114-MEI4-IHO1 higher-order assembly remains incomplete

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0003677 DNA binding 3 GO:0140110 transcription regulator activity 2
Localization
GO:0005694 chromosome 6 GO:0005634 nucleus 2
Pathway
R-HSA-73894 DNA Repair 5 R-HSA-1474165 Reproduction 4 R-HSA-74160 Gene expression (Transcription) 2
Partners
CUF2HORMAD1IHO1MEI1MER2REC102REC114
Complex memberships
REC114-MEI4 heterotrimer (2:1)REC114-MEI4-IHO1/Mer2 pre-DSB complex

Evidence

Reading pass · 20 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1989 S. cerevisiae MEI4 is required for meiotic recombination (gene conversion and crossing over) and acts before RAD52 in the meiotic recombination pathway, as established by genetic epistasis with rad52 and spo13 mutations. Genetic epistasis (double/triple mutant analysis with spo13, rad52); complementation cloning Genetics High 2693205
1992 S. cerevisiae MEI4 encodes a 450-amino-acid meiosis-specific protein required for chromosome synapsis; mei4 mutants form axial elements but fail to undergo synaptonemal complex formation, and MEI4 expression is meiosis-specific and transcriptionally regulated. Cytological analysis of meiotic chromosomes; Northern blot; lacZ fusion reporter Molecular and cellular biology High 1545815
1998 S. pombe Mei4 is a meiosis-specific transcription factor containing a forkhead/HNF3 DNA-binding domain; it binds GTAAAYA consensus sequences in the spo6+ promoter and activates spo6+ transcription, with the C-terminal 140 amino acids constituting the transcriptional activation domain. Gel mobility shift assay (EMSA); one-hybrid assay; promoter deletion analysis; GST fusion protein binding Molecular and cellular biology High 9528784
2000 S. pombe Mei4 binds the FLEX cis-element (17-nucleotide sequence with central GTAAAYA heptamer) and activates at least nine meiotic target genes (mde1–mde9); Mei4 also positively autoregulates its own transcription by binding a FLEX-like element in the mei4 promoter. Genome-wide promoter scanning; Northern blot; EMSA with forkhead domain; reporter gene assay with ectopic Mei4 overproduction Genetics High 10747048
2006 S. cerevisiae Mei4, Rec114, and Mer2 form a distinct protein complex required for meiotic DSB formation; the three proteins co-immunoprecipitate and their chromosome foci partially colocalize. Co-immunoprecipitation; cytological colocalization on meiotic chromosome spreads Genetics High 16783010
2005 In S. pombe, the Rad3-Cds1 replication checkpoint pathway coordinates meiotic DSB formation with premeiotic DNA synthesis by suppressing transcription of the mei4+ transcription factor; mei4+ transcription is restored in cds1Δ cells even when DNA replication is blocked by hydroxyurea. Northern blot; hydroxyurea block; genetic analysis of checkpoint mutants (rad3, cds1, chk1, mek1) The Journal of biological chemistry Medium 16286472
2007 In S. cerevisiae, Mei4 localization to meiotic chromosomes is strongly dependent on Rec114 and Mer2; Rec102 N-terminal sequences are required for interaction with Mei4 and Rec114, connecting the Mei4-Rec114-Mer2 subgroup to Spo11. Protein regions required for the Mei4-Rec114 two-hybrid interaction were mapped by systematic deletion analysis. Chromatin spreading with immunofluorescence; two-hybrid interaction mapping; systematic deletion analysis Chromosoma High 17558514
2010 Mouse MEI4 is functionally conserved for meiotic DSB formation; Mei4−/− mice are deficient in meiotic DSBs, MEI4 localizes to discrete foci on meiotic chromosome axes (not overlapping with DMC1/RPA foci), and mouse MEI4 and REC114 interact directly through conserved motifs. Mouse knockout; cytological analysis (immunofluorescence on chromosome spreads); direct protein interaction assay; mutagenesis of conserved motifs Genes & development High 20551173
2011 S. pombe Rec24 (ortholog of mouse Mei4) is required genome-wide for meiotic crossing-over, localizes to linear elements during prophase in a Rec12-independent manner, and forms complexes in vivo with Rec7 (ortholog of Rec114); Rec7 stabilizes Rec24 on linear elements. Genetic analysis (crossover frequency); cytological localization (immunofluorescence); co-immunoprecipitation Journal of cell science Medium 21429938
2011 S. pombe Mei4 (forkhead transcription factor) is required for telomere dispersal from the spindle pole body at meiosis I onset; mei4Δ mutants arrest with clustered telomeres, and a temperature-sensitive allele (mei4-N136A) carrying a substitution in the forkhead DNA-binding domain allowed synchronization of this event. Live-cell imaging; temperature-sensitive allele analysis; site-directed mutagenesis of forkhead domain Yeast Medium 21449049
2014 In S. pombe, Mei4 (forkhead transcription factor) is required for termination of meiotic nuclear movements; overproduction of Mei4 accelerates termination while its absence prolongs movements, and this regulation is downstream of the Cds1-dependent replication checkpoint. Live-cell microscopy; genetic epistasis (cds1, mei4 mutants); mei4 overexpression Genes to cells Medium 25492408
2015 Mouse MEI4 axis localization requires HORMAD1 (a meiotic chromosome axis component), as well as MEI1, REC8, and RAD21L; the quantitative level of axis-associated MEI4 correlates with DSB frequency, suggesting that axis-associated MEI4 is a limiting factor for DSB formation. Immunofluorescence on meiotic chromosome spreads in multiple mouse mutants; quantitative correlation analysis of MEI4 foci and DSB markers Journal of cell science High 25795304
2016 S. pombe Cuf2 is a transcriptional co-regulator that physically interacts with Mei4 in the nucleus; Cuf2 requires Mei4 and FLEX-like promoter elements for its chromatin occupancy, and together they co-regulate middle-phase meiotic gene expression. Chromatin immunoprecipitation (ChIP); co-immunoprecipitation; bimolecular fluorescence complementation (BiFC); promoter deletion analysis PloS one Medium 26986212
2018 Mouse REC114 is essential for meiotic DSB formation and forms a stable complex with MEI4; the REC114 C-terminal domain directly interacts with the MEI4 N-terminal domain in vitro. The REC114 N-terminal domain has a Pleckstrin homology (PH) domain-like structure. MEI4, REC114, and IHO1 co-localize on meiotic chromosome axes in mouse spermatocytes. Mouse knockout; in vitro reconstitution of complex; crystal structure/structural analysis of REC114 N-terminal domain; cytological co-localization Life science alliance High 30569039
2023 Mouse REC114 forms homodimers and associates with MEI4 as a 2:1 heterotrimer that further dimerizes; IHO1 forms coiled-coil-based tetramers; IHO1 directly interacts with the PH domain of REC114 at the same surface recognized by TOPOVIBL and ANKRD31, suggesting REC114 acts as a regulatory platform with mutually exclusive interactions. Biochemical characterization (SEC-MALS, ITC); AlphaFold2 structural modeling with experimental validation; in vitro binding assays The EMBO journal High 37431931
2023 The Rec114-Mei4 heterotrimeric complex (2:1, Rec114 C-terminus cupping an N-terminal Mei4 α-helix) binds DNA cooperatively and forms large dynamic condensates that can bridge two or more DNA duplexes; the minimal heterotrimer lacking the intrinsically disordered region of Rec114 is sufficient for DNA binding and condensate formation. NMR spectroscopy; structural modeling (AlphaFold2); single-molecule experiments; in vitro DNA binding/condensation assays; mutagenesis Genes & development High 37442580
2023 Rec114-Mei4 and Mer2 complex structures are conserved across eukaryotes: Rec114 C-terminal dimers form α-helical chains cupping the Mei4 N-terminal α-helix; Mer2 forms a parallel homotetrameric coiled coil; both complexes bind branched DNA substrates and Mer2 bridges co-aligned DNA duplexes via electrostatic interactions along the coiled coil. DNA-binding activity of Rec114-Mei4 plays a supportive role while Mer2 condensation is the essential driver. NMR spectroscopy; SAXS; AlphaFold2 modeling; mutagenesis; in vitro DNA-binding assays Genes & development High 37442581
2024 Bi-allelic missense variants in human MEI4 cause preimplantation embryonic arrest and female infertility; the variants reduce MEI4-DNA interaction in vitro, and a knock-in mouse model recapitulates oogenesis defects and female sterility. In vitro DNA-interaction assay with patient variants; knock-in mouse model with oogenesis phenotype analysis Human genetics Medium 38252283
2025 The MEI4 C-terminus stabilizes the MEI4-REC114 subcomplex on chromosome axes; truncation variants (e.g., Arg356*) impair DSB formation and cause massive oocyte apoptosis via HORMAD1-dependent synapsis checkpoint activation, and haploinsufficiency leads to intermediate follicle depletion. Knock-in mouse model; cytological analysis; in vitro DSB formation assay with truncation variants Journal of genetics and genomics Medium 41419020
2025 Mre11/MRX complex forms DNA-dependent condensates that depend on the Mre11 C-terminal IDR, which contains an α-helix that directly binds Mer2; this interaction recruits Mre11 to meiotic DSB sites in a Rec114-Mei4-Mer2 (RMM)-dependent manner. In vitro condensation assay; in vivo foci analysis; mutagenesis of Mre11-Mer2 interface; SUMO-interacting motif analysis bioRxivpreprint Medium bio_10.1101_2025.07.08.663703

Source papers

Stage 0 corpus · 22 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2010 Functional conservation of Mei4 for meiotic DNA double-strand break formation from yeasts to mice. Genes & development 160 20551173
1998 The Schizosaccharomyces pombe mei4+ gene encodes a meiosis-specific transcription factor containing a forkhead DNA-binding domain. Molecular and cellular biology 117 9528784
2007 Interactions between Mei4, Rec114, and other proteins required for meiotic DNA double-strand break formation in Saccharomyces cerevisiae. Chromosoma 110 17558514
2006 Saccharomyces cerevisiae Mer2, Mei4 and Rec114 form a complex required for meiotic double-strand break formation. Genetics 92 16783010
2000 Autoregulated expression of Schizosaccharomyces pombe meiosis-specific transcription factor Mei4 and a genome-wide search for its target genes. Genetics 88 10747048
2018 Mouse REC114 is essential for meiotic DNA double-strand break formation and forms a complex with MEI4. Life science alliance 79 30569039
1989 MEI4, a yeast gene required for meiotic recombination. Genetics 63 2693205
2015 MEI4 – a central player in the regulation of meiotic DNA double-strand break formation in the mouse. Journal of cell science 56 25795304
1992 MEI4, a meiosis-specific yeast gene required for chromosome synapsis. Molecular and cellular biology 50 1545815
2005 Rad3-Cds1 mediates coupling of initiation of meiotic recombination with DNA replication. Mei4-dependent transcription as a potential target of meiotic checkpoint. The Journal of biological chemistry 27 16286472
2011 Functional interactions of Rec24, the fission yeast ortholog of mouse Mei4, with the meiotic recombination-initiation complex. Journal of cell science 21 21429938
2023 Evolutionary conservation of the structure and function of meiotic Rec114-Mei4 and Mer2 complexes. Genes & development 17 37442581
2023 Characterization of the REC114-MEI4-IHO1 complex regulating meiotic DNA double-strand break formation. The EMBO journal 16 37431931
2023 Structure and DNA-bridging activity of the essential Rec114-Mei4 trimer interface. Genes & development 12 37442580
2011 A novel fission yeast mei4 mutant that allows efficient synchronization of telomere dispersal and the first meiotic division. Yeast (Chichester, England) 11 21449049
2014 Meiotic nuclear movements in fission yeast are regulated by the transcription factor Mei4 downstream of a Cds1-dependent replication checkpoint pathway. Genes to cells : devoted to molecular & cellular mechanisms 10 25492408
2024 Bi-allelic missense variants in MEI4 cause preimplantation embryonic arrest and female infertility. Human genetics 9 38252283
2020 Genetic Interactions of Histone Modification Machinery Set1 and PAF1C with the Recombination Complex Rec114-Mer2-Mei4 in the Formation of Meiotic DNA Double-Strand Breaks. International journal of molecular sciences 6 32290544
2016 Cuf2 Is a Transcriptional Co-Regulator that Interacts with Mei4 for Timely Expression of Middle-Phase Meiotic Genes. PloS one 3 26986212
2023 Structure and DNA bridging activity of the essential Rec114â€"Mei4 trimer interface. bioRxiv : the preprint server for biology 1 36711595
2026 Mei4 deficiency induces sexual dimorphism in early meiosis and promotes production of unreduced eggs in zebrafish. Zoological research 0 42011758
2025 MEI4 variations drive female reproductive disorders via impaired oocyte abundance and developmental potential. Journal of genetics and genomics = Yi chuan xue bao 0 41419020