NCBI Summary:
The protein encoded by this gene belongs to the inhibitor of DNA binding family, members of which are transcriptional regulators that contain a helix-loop-helix (HLH) domain but not a basic domain. Members of the inhibitor of DNA binding family inhibit the functions of basic helix-loop-helix transcription factors in a dominant-negative manner by suppressing their heterodimerization partners through the HLH domains. This protein may play a role in negatively regulating cell differentiation. A pseudogene of this gene is located on chromosome 3. [provided by RefSeq, Aug 2011]
General function
Nucleic acid binding, DNA binding, Transcription factor
Single-cell RNA-Seq reveals a highly coordinated transcriptional program in mouse germ cells during primordial follicle formation. He Y et al. (2021) The assembly of primordial follicles in mammals represents one of the most critical processes in ovarian biology. It directly affects the number of oocytes available to a female throughout her reproductive life. Premature depletion of primordial follicles contributes to the ovarian pathology primary ovarian insufficiency (POI). To delineate the developmental trajectory and regulatory mechanisms of oocytes during the process, we performed RNA-seq on single germ cells from newborn (P0.5) ovaries. Three cell clusters were classified which corresponded to three cell states (germ cell cyst, cyst breakdown, and follicle) in the newborn ovary. By Monocle analysis, a uniform trajectory of oocyte development was built with a series of genes showed dynamic changes along the pseudo-timeline. Gene Ontology term enrichment revealed a significant decrease in meiosis-related genes and a dramatic increase in oocyte-specific genes which marked the transition from a germ cell to a functional oocyte. We then established a network of regulons by using single-cell regulatory network inference and clustering (SCENIC) algorithm and identified possible candidate transcription factors that may maintain transcription programs during follicle formation. Following functional studies further revealed the differential regulation of the identified regulon Id2 and its family member Id1, on the establishment of primordial follicle pool by using siRNA knockdown and genetic modified mouse models. In summary, our study systematically reconstructed molecular cascades in oocytes and identified a series of genes and molecular pathways in follicle formation and development.////////////////// Expression and localization of Inhibitor of Differentiation (ID) proteins during tissue and vascular remodelling in the human corpus luteum. Nio-Kobayashi J et al. Members of the transforming growth factor-?(TGF-? superfamily are likely to have major roles the regulation of tissue and vascular remodelling in the corpus luteum. There are four Inhibitor of Differentiation (ID1-4) genes that are regulated by members of the TGF-?superfamily and are involved in the transcriptional regulation of cell growth and differentiation. We studied their expression, localisation and regulation in dated human corpora lutea from across the luteal phase (n=22) and after human chorionic gonadotrophin (hCG) administration in vivo (n=5), and in luteinised granulosa cells (LGCs), using immunohistochemistry and quantitative RT-PCR. ID1-4 can be localised to multiple cell types in the corpus luteum across the luteal phase. Endothelial cell ID3 (P<0.05) and ID4 (P<0.05) immunostaining intensities peak at the time of angiogenesis but overall ID1 (P<0.05) and ID3 (P<0.05) expression peaks at the time of luteolysis and luteal ID3 expression is inhibited by hCG in vivo (P<0.01). In LGC cultures in vitro, hCG had no effect on ID1, down-regulated ID3 (P<0.001), and up-regulated ID2 (P<0.001) and ID4 (P<0.01). Bone morphogenic proteins (BMPs) had no effect on ID4 expression but up-regulated ID1 (P<0.01-P<0.005). BMP up-regulation of ID2 (P<0.05) was additive to the hCG upregulation of ID2 expression (P<0.001), while BMP cancelled out the down regulative effect of hCG on ID3 regulation. As well as documenting regulation patterns specific for ID1, ID2, ID3 and ID4, we have shown that IDs are located and differentially regulated in the human corpus luteum, suggesting a role in the transcriptional regulation of luteal cells during tissue and vascular remodelling.
Expression regulated by
FSH, Growth Factors/ cytokines, mir
Comment
Regulation of ACVR1 and ID2 by cell-secreted exosomes during follicle maturation in the mare. da Silveira JC 2014 et al.
BACKGROUND
Ovarian follicle growth and maturation requires extensive communication between follicular somatic cells and oocytes. Recently, intercellular cell communication was described involving cell-secreted vesicles called exosomes (50-150 nm), which contain miRNAs and protein, and have been identified in ovarian follicular fluid. The goal of this study was to identify a possible role of exosomes in follicle maturation.
METHODS
Follicle contents were collected from mares at mid-estrous (~35 mm, before induction of follicular maturation) and pre-ovulatory follicles (30-34 h after induction of follicular maturation). A real time PCR screen was conducted to reveal significant differences in the presence of exosomal miRNAs isolated from mid-estrous and pre-ovulatory follicles, and according to bioinformatics analysis these exosomal miRNAs are predicted to target members belonging to the TGFB superfamily, including ACVR1 and ID2. Granulosa cells from pre-ovulatory follicles were cultured and treated with exosomes isolated from follicular fluid. Changes in mRNA and protein were measured by real time PCR and Western blot.
RESULTS
ACVR1 mRNA and protein was detected in granulosa cells at mid-estrous and pre-ovulatory stages, and real time PCR analysis revealed significantly lower levels of ID2 (an ACVR1 target gene) in granulosa cells from pre-ovulatory follicles. Exposure to exosomes from follicular fluid of mid-estrous follicles decreased ID2 levels in granulosa cells. Moreover, exosomes isolated from mid-estrous and pre-ovulatory follicles contain ACVR1 and miR-27b, miR-372, and miR-382 (predicted regulators of ACVR1 and ID2) were capable of altering ID2 levels in pre-ovulatory granulosa cells.
CONCLUSIONS
These data indicate that exosomes isolated from follicular fluid can regulate members of the TGFB/BMP signaling pathway in granulosa cells, and possibly play a role in regulating follicle maturation.
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Identification of genes targeted by FSH and oocytes in porcine granulosa cells. Verbraak EJ et al. In the mammalian ovarian follicle maturing oocytes are nurtured and supported by surrounding somatic cells, the mural granulosa cells and the cumulus cells. These cells are regulated by follicle-stimulating hormone (FSH), originating from the pituitary, and paracrine factors derived from the oocyte. To gain insight into the mechanisms involved in the regulation of granulosa cell function, this study aimed to identify genes in mural granulosa cells that are regulated by FSH and oocyte secreted factors using the pig as a model organism. Mural granulosa cells were collected from 3-6 mm follicles from sow ovaries and cultured in serum free medium in the presence or absence of FSH and/or isolated cumulus oocyte complexes (COCs). FSH significantly increased both the metabolic activity and progesterone production of granulosa cells, while the presence of COCs reversed these FSH effects. Expression levels of mRNA in the absence/presence of FSH and COCs were analyzed on porcine specific microarrays representing 11,300 genes. Both previously identified and novel FSH target genes as well as some oocyte affected genes were found. Expression of inhibitor of DNA binding protein 2 and 3, ID2 and ID3, was decreased by FSH but increased by COCs, as validated by quantitative PCR. These proteins function as dominant negative basic helix loop helix (bHLH) transcription factors and since all regulated genes contain the consensus E-box sequence that can bind bHLH factors, our data suggest that FSH and COCs may regulate granulosa cell function by tuning the activity of bHLH factors, through ID2 and ID3.
Inhibitor of Differentiation (Id) Genes Are Expressed in the Steroidogenic Cells of the Ovine Ovary and Are Differentially Regulated by Members of the Transforming Growth Factor-{beta} Family. Hogg K et al. Inhibitor of differentiation (Id) proteins act during embryogenesis and development to repress gene transcription required for lineage commitment, while promoting cell growth. Growth factors belonging to the TGFbeta superfamily of signaling molecules, notably the bone morphogenetic proteins (BMPs) and activin, can regulate Id expression in these tissues. Id expression and function in adult physiology is less well determined, and we hypothesized a role for Id proteins in the adult mammalian ovary. Immunohistochemistry for Id1, Id2, Id3, and Id4 in the sheep ovary revealed consistent expression in granulosa and thecal cells of ovarian follicles throughout development. In atretic follicles, Id proteins were selectively down-regulated in thecal cells (P < 0.0001). Additionally, Id1 was universally up-regulated in the cumulus cells adjacent to the oocyte. Immunohistochemistry for phospho (p)-smad 1/5/8 signaling components (stimulated by BMPs) showed a punctate pattern of expression whereas p-smad 2/3 (stimulated by activin) was ubiquitously expressed in follicles. Neither pathway, however, displayed differential staining in line with Id1 cumulus-specific expression, suggesting a more complex relationship between Id1 expression and TGFbeta signaling in these cells. Nevertheless, in vitro, stimulation of ovine granulosa cells with BMP6 or activin A led to a respective increase and decrease in Id1 (P < 0.0001), Id2 (P < 0.0001), Id3 (P < 0.0001), and Id4 (P < 0.05) transcripts, and Id1 gene expression was further manipulated by the oocyte-secreted factors BMP15 and growth differentiation factor 9 (P < 0.001). These data confirm that TGFbeta signaling can regulate Id gene expression in the sheep ovarian follicle and suggest a functional role for the Id family in the mammalian ovary.
Ovarian localization
Cumulus, Granulosa, Theca, Luteal cells
Comment
Changes in mouse granulosa cell gene expression during early luteinization. McRae RS et al. Changes in gene expression during granulosa cell luteinization have been measured using serial analysis of gene expression (SAGE). Immature normal mice were treated with pregnant mare serum gonadotropin (PMSG) or PMSG followed, 48 h later, by human chorionic gonadotropin (hCG). Granulosa cells were collected from preovulatory follicles after PMSG injection or PMSG/hCG injection and SAGE libraries generated from the isolated mRNA. The combined libraries contained 105,224 tags representing 40,248 unique transcripts. Overall, 715 transcripts showed a significant difference in abundance between the two libraries of which 216 were significantly down-regulated by hCG and 499 were significantly up-regulated. Among transcripts differentially regulated, there were clear and expected changes in genes involved in steroidogenesis as well as clusters of genes involved in modeling of the extracellular matrix, regulation of the cytoskeleton and intra and intercellular signaling. The SAGE libraries described here provide a base for functional investigation of the regulation of granulosa cell luteinization.
Follicle stages
Comment
Role for Inhibitor of Differentiation/DNA Binding (Id) Proteins in Granulosa Cell Differentiation. Johnson AL et al. Recent studies in the hen ovary have linked the initiation of granulosa cell differentiation at follicle selection to the alleviation of inhibitory MAPK signaling. The present studies assessed a role for individual Id (inhibitor of differentiation) protein isoforms as modulators of key transcriptional events occurring within granulosa cells at or immediately subsequent to differentiation. Findings from freshly collected granulosa cells collected at different stages of follicle development demonstrated a negative association between expression levels for Id2 mRNA compared to levels of Id1, Id3 and Id4. Elevated levels of Id2 are related to a differentiating/differentiated phenotype, whereas elevated Id1, Id3 and Id4 are associated with an undifferentiated phenotype. This negative relationship extends to cell signal transduction, as factors that promote inhibitory MAPK signaling (transforming growth factor alpha and betacellulin) block expression of Id2 mRNA but increase levels of Id1, Id3 and Id4. Furthermore, over-expression of Gallus Id2 in cultured granulosa was found to significantly decrease levels of Id1, Id3 and Id4 mRNA, but facilitate FSHR mRNA expression and, importantly, initiate LHR mRNA expression plus LH-induced progesterone production. Finally, knock-down studies using siRNA specific for Id2 revealed reduced expression of FSHR and LHR mRNA, and attenuated FSH- and LH-induced levels of StAR and p450 cholesterol side chain cleavage enzyme mRNA plus progesterone production. Collectively, these data demonstrate that Id2 expression is both sufficient and necessary for increasing LHR expression and, as a result, promoting gonadotropin-induced differentiation in hen granulosa cells subsequent to follicle selection.