Affinage

FIGLA

Factor in the germline alpha · UniProt Q6QHK4

Length
219 aa
Mass
24.1 kDa
Annotated
2026-06-09
29 papers in source corpus 13 papers cited in narrative 13 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

FIGLA is an oocyte-specific basic helix-loop-helix (bHLH) transcription factor that governs the perinatal transition from cystic oocytes to individual primordial follicles and orchestrates the oocyte-specific gene expression program (PMID:11023867, PMID:30184072). It functions by heterodimerizing with the ubiquitous bHLH partner E12/TCF3 and binding E-box elements in the promoters of the zona pellucida genes ZP1, ZP2, and ZP3, transactivating their expression; this activity is conserved between mouse and human (PMID:9362457, PMID:15044608). Beyond zona pellucida regulation, FIGLA operates within a cooperative germ-cell transcription factor network, physically interacting with LHX8 and SOHLH1 and cross-regulating the abundance of NOBOX, SOHLH1/2, and KIT, with its loss impeding meiotic progression, causing DNA damage, and triggering perinatal oocyte apoptosis (PMID:27716808, PMID:32086523, PMID:24400092). Genetic ablation in mouse and zebrafish establishes FIGLA as essential and non-redundant for follicle formation, acting in a pathway distinct from steroid hormone and p53-dependent apoptotic signaling and upstream of NOBOX-dependent follicle growth (PMID:11023867, PMID:30184072, PMID:37990081). Multiple loss-of-function and missense mutations that disrupt TCF3 binding or ZP promoter transactivation cause premature ovarian insufficiency in women (PMID:18499083, PMID:30474133, PMID:34778283). Post-transcriptionally, maternal FIGLA mRNA is repressed by miR-212 binding its 3' UTR during the maternal-to-zygotic transition (PMID:24086699).

Mechanistic history

Synthesis pass · year-by-year structured walk · 13 steps
  1. 1997 High

    Established the founding molecular activity of FIGLA: how an oocyte factor could coordinately switch on the zona pellucida genes, by showing it is a bHLH protein that dimerizes with E12 and binds E-boxes in all three Zp promoters.

    Evidence EMSA and luciferase reporter transactivation in heterologous fibroblasts for mouse Zp1/Zp2/Zp3 promoters

    PMID:9362457

    Open questions at the time
    • Done in heterologous fibroblasts, not native oocytes
    • Full set of in vivo target genes beyond Zp genes unknown
    • No structural basis for E-box selectivity
  2. 2000 High

    Demonstrated that FIGLA is physiologically required for primordial follicle formation and female fertility, moving it from a candidate Zp regulator to a master regulator of folliculogenesis.

    Evidence Targeted knockout in mice with histology and RT-PCR of downstream genes

    PMID:11023867

    Open questions at the time
    • Direct vs. indirect cause of oocyte depletion not separated
    • Mechanism linking FIGLA loss to follicle formation failure unresolved
    • Male dispensability unexplained
  3. 2004 High

    Extended the FIGLA-E12/ZP2 mechanism to humans and confirmed it occurs in native tissue, validating the mouse model for human ovarian biology.

    Evidence EMSA with recombinant human FIGLA and human fetal ovary nuclear extracts

    PMID:15044608

    Open questions at the time
    • Only ZP2 promoter tested in human
    • No functional transactivation shown for human promoters here
  4. 2008 Medium

    Linked FIGLA to human disease and pinpointed the mechanism: an HLH-domain deletion in a POI patient abolishes the TCF3/E12 interaction required for DNA binding.

    Evidence Yeast two-hybrid comparing wild-type and p.140delN FIGLA against TCF3 HLH domain

    PMID:18499083

    Open questions at the time
    • Single method (Y2H) without biochemical reconstitution
    • Causality in patient not proven beyond interaction loss
    • Effect on downstream transactivation not measured
  5. 2013 Medium

    Identified post-transcriptional control of FIGLA, showing maternal FIGLA mRNA is actively repressed by miR-212 during the maternal-to-zygotic transition.

    Evidence Luciferase reporter with FIGLA 3' UTR and miR-212 mimic overexpression in bovine embryos

    PMID:24086699

    Open questions at the time
    • Shown in bovine; conservation in human/mouse not tested
    • Physiological consequence of repression on embryo not defined
    • Single lab
  6. 2014 Medium

    Resolved the fate of oocytes lost perinatally, showing intra-ovarian apoptosis rather than egress or macrophage-driven clearance drives the loss.

    Evidence Live imaging of Figla-Cre reporter newborn ovaries, Csf1op/op macrophage depletion, TUNEL and caspase inhibitor experiments

    PMID:24400092

    Open questions at the time
    • Causal link between FIGLA activity and apoptosis not directly tested here
    • Reporter marks germ cells but does not assay FIGLA function
    • Single lab
  7. 2016 Medium

    Began assembling the germ-cell transcription factor network by showing FIGLA physically interacts with the LIM-homeobox factor LHX8.

    Evidence Protein interaction assay and subcellular localization with deletion constructs in bovine system

    PMID:27716808

    Open questions at the time
    • Interaction detected with limited methodological detail
    • Functional consequence of FIGLA-LHX8 binding not defined here
    • Interaction interface unmapped
  8. 2018 High

    Placed FIGLA in a defined epistatic pathway for the cyst-to-follicle transition, distinct from estrogen signaling and p53-dependent apoptosis, using zebrafish loss-of-function and rescue logic.

    Evidence CRISPR/Cas9 figla knockout in zebrafish with estrogen rescue and tp53 double-mutant epistasis, histology and transcriptomics

    PMID:30184072

    Open questions at the time
    • Molecular targets driving the cyst-to-follicle block not identified
    • All-male phenotype mechanism in fish vs. mammals differs
    • Direct vs. indirect transcriptional effects unseparated
  9. 2018 Medium

    Strengthened FIGLA as a POI gene by identifying a start-codon mutation that ablates full-length protein synthesis without affecting transcription, recapitulating a knockout-like state.

    Evidence In vitro protein synthesis assay of c.2T>C construct, whole-genome and Sanger sequencing of two affected sisters

    PMID:30474133

    Open questions at the time
    • In vitro translation only; no patient-derived protein measured
    • Functional ovarian consequence inferred from knockout analogy
    • Single family
  10. 2020 High

    Defined the cooperative core of the network, showing FIGLA, LHX8 and SOHLH1 mutually interact and cross-regulate, and that FIGLA loss disrupts meiotic progression, causes DNA damage, and triggers apoptosis.

    Evidence RNA-seq across FiglaNull/Lhx8Null/Sohlh1Null mice, co-IP protein interaction assays, immunofluorescence, and DNA damage/apoptosis readouts

    PMID:32086523

    Open questions at the time
    • Direct FIGLA target promoters vs. secondary network effects not fully separated
    • Order of network activation not resolved
    • Mechanism connecting FIGLA loss to DNA damage unclear
  11. 2021 Medium

    Refined FIGLA's transactivation defect as the disease mechanism, showing POF-associated missense variants reduce ZP promoter binding and transcriptional activation.

    Evidence ChIP of wild-type vs. mutant FIGLA on ZP promoters and luciferase reporter assays in HEK293 cells

    PMID:34778283

    Open questions at the time
    • Performed in heterologous HEK293 cells
    • In vivo consequence in patient oocytes not shown
    • Single lab
  12. 2021 Medium

    Extended FIGLA function beyond primordial follicle formation, showing a stage- and age-specific role in promoting secondary follicle growth in adult oocytes.

    Evidence Figla siRNA microinjection into secondary follicle oocytes with in vitro growth assay and transcriptomic pathway analysis

    PMID:33972571

    Open questions at the time
    • Pathway changes (VDR/RXR, estrogen) inferred from transcriptomics, not validated
    • Limited mechanistic follow-up
    • Single lab
  13. 2023 High

    Ordered the network in vivo by epistasis, placing figla specifically at the cyst-to-follicle transition upstream of nobox-dependent follicle growth and aromatase/estrogen signaling.

    Evidence CRISPR figla-/-;dmrt1-/- and nobox-/-;dmrt1-/- zebrafish double mutants with histology, gene expression, estradiol measurement and E2 rescue

    PMID:37990081

    Open questions at the time
    • Direct transcriptional targets mediating the cyst-to-follicle step unidentified
    • Mammalian conservation of figla-nobox ordering not directly tested
    • How figla loss arrests cells in cysts molecularly unresolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • The complete genome-wide set of direct FIGLA targets and the structural/biochemical basis by which the FIGLA-E12 dimer selects oocyte-specific E-boxes remain undefined.
  • No ChIP-seq/CUT&RUN target catalog
  • No structure of FIGLA-E12-DNA complex
  • Mechanism linking transcriptional output to meiotic progression and DNA-damage avoidance unresolved

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140110 transcription regulator activity 4 GO:0003677 DNA binding 3
Localization
GO:0005634 nucleus 1
Pathway
R-HSA-1266738 Developmental Biology 3 R-HSA-1474165 Reproduction 3 R-HSA-74160 Gene expression (Transcription) 2
Partners
LHX8SOHLH1TCF3

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1997 FIGLA (FIGalpha) is a novel basic helix-loop-helix transcription factor that heterodimerizes with the ubiquitous bHLH protein E12 and binds E-box elements (~200 bp upstream of transcription start sites) in the promoters of all three zona pellucida genes (Zp1, Zp2, Zp3); FIGLA transactivates reporter genes coupled to each of the three mouse zona promoters in heterologous 10T1/2 embryonic fibroblasts. Electrophoretic mobility shift assay (EMSA), co-immunoprecipitation/protein-DNA complex identification, luciferase reporter transactivation in heterologous fibroblasts Development High 9362457
2000 Targeted knockout of FIGalpha in mice causes failure of primordial follicle formation at birth, massive postnatal oocyte depletion, shrunken ovaries, and female sterility; null females fail to express Zp1, Zp2, or Zp3, establishing FIGLA as a key regulator of multiple oocyte-specific genes including zona pellucida genes and genes initiating folliculogenesis. Male FIGalpha null mice are fertile with no obvious phenotype. Targeted gene knockout in mouse embryonic stem cells, histology, RT-PCR for downstream gene expression Development High 11023867
2004 Human FIGLA protein heterodimerizes with E12 and binds the E-box of the human ZP2 promoter, as demonstrated by EMSA with in vitro-expressed human FIGLA; similar mobility shifts were detected in human fetal ovary extracts, confirming the interaction occurs in vivo. EMSA with in vitro-expressed human FIGLA protein and human fetal ovary nuclear extracts Molecular human reproduction High 15044608
2008 A FIGLA missense mutation p.140delN (deletion of asparagine 140 in the HLH domain) found in a woman with premature ovarian failure disrupts FIGLA binding to the TCF3 (E12) helix-loop-helix domain, as demonstrated by yeast two-hybrid assay. Yeast two-hybrid assay comparing wild-type and mutant FIGLA interaction with TCF3 HLH domain American journal of human genetics Medium 18499083
2013 MicroRNA-212 (miR-212) post-transcriptionally represses FIGLA expression by binding a microRNA recognition element (MRE) in the 3' UTR of bovine FIGLA mRNA; ectopic miR-212 expression in bovine early embryos reduces FIGLA protein levels, identifying miR-212 as a negative regulator of FIGLA during the maternal-to-zygotic transition. Luciferase reporter assay with FIGLA 3' UTR, miR-212 mimic overexpression in bovine embryos with FIGLA protein quantification PloS one Medium 24086699
2016 Bovine LHX8, a germ-cell-specific LIM-homeobox transcription factor, physically interacts with FIGLA; a nuclear localization signal in LHX8 is required for its nuclear import, and LHX8 is predominantly nuclear when ectopically expressed. Co-immunoprecipitation/yeast two-hybrid-like protein interaction assay (interaction detected); subcellular localization by fluorescence microscopy with deletion constructs PloS one Medium 27716808
2018 In zebrafish, CRISPR/Cas9-mediated disruption of figla blocks the transition of cystic CN-stage oocytes to individual follicular perinucleolar oocytes (stage IB), resulting in an all-male phenotype; this phenotype cannot be rescued by estrogen treatment (unlike cyp19a1a mutants) or by tp53 mutation (unlike fancd1/fancl mutants), placing figla in a distinct epistatic pathway from steroid hormone signaling and p53-dependent apoptosis. CRISPR/Cas9 knockout in zebrafish, epistasis analysis with cyp19a1a mutants (estrogen rescue), tp53 double mutants, histological and transcriptomic analysis Endocrinology High 30184072
2018 A homozygous FIGLA mutation c.2T>C (p.Met1Thr) found in two sisters with POI blocks synthesis of full-length FIGLA protein (start codon shift) without affecting FIGLA gene transcription, producing a FIGLA knockout-like phenotype. In vitro functional analysis of mutant construct (protein synthesis assay), whole-genome sequencing, Sanger sequencing Clinical genetics Medium 30474133
2020 FIGLA, LHX8, and SOHLH1 physically interact with each other in perinatal oocytes and cross-regulate each other's expression; Figla deficiency disrupts abundance of NOBOX, LHX8, SOHLH1, SOHLH2, and KIT, impedes meiotic progression, causes DNA damage, and results in oocyte apoptosis. Dysregulated genes include meiosis-related genes (Sycp3, Rad51, Ybx2) and oocyte growth genes (Nobox, Lhx8, Taf4b, Sohlh1, Sohlh2, Gdf9). RNA-seq of perinatal ovaries from FiglaNull, Lhx8Null, and Sohlh1Null mice; co-immunoprecipitation/direct protein interaction assays; immunofluorescence for protein abundance; DNA damage assays (presumably γH2AX or TUNEL); gene expression profiling Nucleic acids research High 32086523
2021 siRNA-mediated knockdown of Figla in secondary follicle oocytes of mature (but not prepubertal) mice reduces follicle diameter growth in vitro, suggesting Figla promotes secondary follicle growth specifically in adult mice; pathway analysis indicates Figla upregulates VDR/RXR activation and downregulates estrogen signaling and stem cell pluripotency pathways. Figla siRNA microinjection into secondary follicle oocytes followed by in vitro follicle growth assay; transcriptomic pathway analysis Scientific reports Medium 33972571
2021 FIGLA mutations (p.A4E, p.V209I, p.D28E) found in POF patients significantly reduce FIGLA binding to ZP1, ZP2, and ZP3 promoters and reduce transcriptional activation of ZP1, ZP2, and ZP3 reporter genes. Chromatin immunoprecipitation (ChIP) comparing wild-type vs. mutant FIGLA binding to ZP promoters; luciferase reporter assay in HEK293 cells Frontiers in medicine Medium 34778283
2023 In zebrafish, epistasis analysis using figla-/-;dmrt1-/- double mutants shows germ cells remain in cysts without forming follicles in the absence of figla, whereas nobox-/-;dmrt1-/- fish form follicles that arrest at the previtellogenic stage; this places figla specifically upstream of follicle formation (cyst-to-follicle transition) and nobox upstream of subsequent follicle growth and estrogen/aromatase signaling. CRISPR/Cas9-generated double mutants (figla-/-;dmrt1-/- and nobox-/-;dmrt1-/-), histology, expression analysis of cyp19a1a and other pathway genes, serum estradiol measurement, E2 rescue experiment Communications biology High 37990081
2014 Live imaging of Figla-Cre;mEGFP/mTomato reporter mice (germ cells green, somatic tissue red) in newborn ovaries shows that few oocytes egress from the ovary and the vast majority are lost within the ovary; macrophage depletion (Csf1op/op mice) does not prevent oocyte loss, but TUNEL assays and caspase inhibitor experiments indicate apoptosis contributes to perinatal oocyte loss. Live confocal imaging of cultured newborn ovaries, macrophage depletion genetic model (Csf1op/op), TUNEL assay, caspase inhibitor treatment PloS one Medium 24400092

Source papers

Stage 0 corpus · 29 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2000 FIGalpha, a germ cell-specific transcription factor required for ovarian follicle formation. Development (Cambridge, England) 402 11023867
1997 FIGalpha, a germ cell specific transcription factor involved in the coordinate expression of the zona pellucida genes. Development (Cambridge, England) 232 9362457
2008 Transcription factor FIGLA is mutated in patients with premature ovarian failure. American journal of human genetics 148 18499083
2020 FIGLA, LHX8 and SOHLH1 transcription factor networks regulate mouse oocyte growth and differentiation. Nucleic acids research 85 32086523
2002 Isolation, characterization and expression of the human Factor In the Germline alpha (FIGLA) gene in ovarian follicles and oocytes. Molecular human reproduction 63 12468641
2004 Increased expression of the FIGLA transcription factor is associated with primordial follicle formation in the human fetal ovary. Molecular human reproduction 60 15044608
2018 Roles of Figla/figla in Juvenile Ovary Development and Follicle Formation During Zebrafish Gonadogenesis. Endocrinology 51 30184072
2016 Two Figla homologues have disparate functions during sex differentiation in half-smooth tongue sole (Cynoglossus semilaevis). Scientific reports 29 27313147
2013 MicroRNA-212 post-transcriptionally regulates oocyte-specific basic-helix-loop-helix transcription factor, factor in the germline alpha (FIGLA), during bovine early embryogenesis. PloS one 29 24086699
2012 Characterization of female germ-like cells derived from mouse embryonic stem cells through expression of GFP under the control of Figla promoter. Journal of cellular biochemistry 29 22213070
2015 Figla Favors Ovarian Differentiation by Antagonizing Spermatogenesis in a Teleosts, Nile Tilapia (Oreochromis niloticus). PloS one 28 25894586
2015 Mutational analysis of the FIGLA gene in women with idiopathic premature ovarian failure. Menopause (New York, N.Y.) 27 25314148
2018 Consanguineous familial study revealed biallelic FIGLA mutation associated with premature ovarian insufficiency. Journal of ovarian research 26 29914564
2008 Comparative genomics approach to the expression of figalpha, one of the earliest marker genes of oocyte differentiation in medaka (Oryzias latipes). Gene 22 18678233
2023 Genetic evidence for differential functions of figla and nobox in zebrafish ovarian differentiation and folliculogenesis. Communications biology 13 37990081
2018 Bi-allelic recessive loss-of-function mutations in FIGLA cause premature ovarian insufficiency with short stature. Clinical genetics 13 30474133
2014 Figla-Cre transgenic mice expressing myristoylated EGFP in germ cells provide a model for investigating perinatal oocyte dynamics. PloS one 12 24400092
2014 Responsiveness of four gender-specific genes, figla, foxl2, scp3 and sox9a to 17α-ethinylestradiol in adult rare minnow Gobiocypris rarus. General and comparative endocrinology 12 24631545
2016 bmp15l, figla, smc1bl, and larp6l are preferentially expressed in germ cells in Atlantic salmon (Salmo salar L.). Molecular reproduction and development 10 27893173
2022 Absence of Figla-like Gene Is Concordant with Femaleness in Cichlids Harboring the LG1 Sex-Determination System. International journal of molecular sciences 9 35886982
2016 Bovine Lhx8, a Germ Cell-Specific Nuclear Factor, Interacts with Figla. PloS one 9 27716808
2021 Figla promotes secondary follicle growth in mature mice. Scientific reports 8 33972571
2017 Robust gdf9 and bmp15 expression in the oocytes of ovotestes through the Figla-independent pathway in the hermaphroditic black porgy, Acanthopagrus schlegelii. PloS one 8 29073214
2021 Mutations in FIGLA Associated With Premature Ovarian Insufficiency in a Chinese Population. Frontiers in medicine 4 34778283
2024 Molecular Characterization, Expression Pattern, DNA Methylation and Gene Disruption of Figla in Blotched Snakehead (Channa maculata). Animals : an open access journal from MDPI 3 38338134
2020 Transcriptional activity of FIGLA, NEUROG2, and EGR1 transcription factors associated with polymorphisms in the proximal regulatory region of GPR54 gene in cattle. Animal reproduction science 3 32507252
2015 A lentiviral vector visualizing the germ cell specification in vitro under the control of Figla promoter. Applied biochemistry and biotechnology 3 25652828
2025 Homozygous FIGLA missense variant in two Japanese sisters with primary ovarian insufficiency: Case reports and literature review. Reproductive medicine and biology 1 39896098
2026 A duplicated female pathway gene figla-like evolves as the male sex-determining gene in tilapia. Journal of genetics and genomics = Yi chuan xue bao 0 42140582

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