Project description:The identity of the gonads is determined by which fate, ovarian granulosa cell or testicular Sertoli cell, the bipotential somatic cell precursors choose to follow. In most vertebrates, the fate of granulosa cells is controlled by a conserved regulator FOXL2. To understand how FOXL2 elicits its fate-determining action, we performed genome-wide analysis of FOXL2 chromatin occupancy in fetal ovaries. Combining genome-wide analysis of FOXL2 binding in the fetal ovary with transcriptomic analyses of Foxl2 gain-of-function and Foxl2 loss-of-function models, we identified potential pathways responsible for the feminizing action of FOXL2. Finally, comparison of FOXL2 genome-wide occupancy in the fetal ovary with testis-determining factor SOX9 genome-wide occupancy in the fetal testis revealed extensive overlaps, implying that antagonistic signals between FOXL2 and SOX9 occur at the chromatin level.
Project description:We discovered that expression of the transcription factor RUNX1 is enriched in the fetal ovary in various vertebrate species. In the mouse, RUNX1 marks the supporting cell lineage and becomes granulosa cell-specific as the gonads differentiate. To understand the function of Runx1 during fetal development of the ovary, we ablated Runx1 specifically in the somatic cell lineage of the fetal ovaries using Sf1-Cre . We compared ovarian differentiation in wild type, Runx1 and Foxl2 single knockouts, and Runx1/Foxl2 double knockout ovaries. Transcriptome comparisons of newborn ovaries revealed that loss of Runx1 or Foxl2 affected a similar set of genes: 41% of the genes affected by the loss of Runx1 were also changed by the loss of Foxl2. Despite these transcriptomic changes, granulosa cell identity was maintained during fetal life in both Runx1 or Foxl2 single knockout ovaries. However, the combined loss of Runx1/Foxl2 resulted in masculinization of the ovaries during fetal life. To further characterize the impacts of the combined loss of Runx1 and Foxl2 on ovarian differentiation, we compared the transcriptome of Runx1/Foxl2 DKO newborn ovaries with the transcriptomes of control, Runx1, or Foxl2 single KO ovaries.
Project description:Sex determination of the gonads begins with fate specification of gonadal supporting cells into either ovarian granulosa cells or testicular Sertoli cells. This process of fate specification hinges on a balance of transcriptional control. We discovered that the transcription factor RUNX1 is enriched in the fetal ovary in rainbow trout, turtle, mouse, and human. In the mouse, RUNX1 marks the supporting cell lineage and becomes granulosa cell-specific as the gonads differentiate. RUNX1 plays complementary/redundant roles with FOXL2 to maintain fetal granulosa cell identity, and combined loss of RUNX1 and FOXL2 results in masculinization of the fetal ovaries. To determine whether interplay between RUNX1 and FOXL2 occurs at the chromatin level, we performed genome-wide analysis of RUNX1 chromatin occupancy in E14.5 ovaries. The top de novo motif identified in RUNX1 ChIP-seq matched the RUNX motif. We found that RUNX1 chromatin occupancy was partially overlapping with FOXL2 chromatin occupancy in fetal ovaries.
Project description:Comparison of Foxl2-null ovaries to wildtype ovaries, ovaries lacking Wnt4 or Kit, or testes, throughout mouse development. The goal of this study was to identify early Foxl2 target genes as well as other ovarian, anti-testis genes that may act independently of Foxl2. Experiment Overall Design: We studied 43 samples over 15 conditions to cover a wide range of wiltype and pathological states showing highly divergent alterations of cell type composition. This was meant to identify the most specific, cell context-independent targets of Foxl2.
Project description:Foxl2 is a forkhead transcription factor expressed only in the female, but not in the male gonad. We have created mice homozygous mutant for the Foxl2 gene (KO) as well as mice carrying a conditional mutant Foxl2 allele (floxed). The expression profiles of conventional Foxl2 knockout and wildtype ovaries were compared at P3, using the Affy Mouse Genome 430 2.0 Array. Adult wildtype and conditional mutant (Foxl2 floxed x RosaCre-EBD treated with tamoxifen) ovaries were compared to adult wildtype testes using the Affymetrix Mouse Gene 1.0 ST Array. Both experiments (KO/WT P3 and Mutant/WT/Testis Adult were also compared to each other.)
Project description:From fish to human, FOXL2 is considered one of the most conserved markers of ovarian granulosa cell identity. To determine if the sole expression of FOXL2 can determine ovarian differentiation, we created a mouse model that allows the conditional expression of FOXL2. Rosa26-CAG-LSL-Foxl2 mice were crossed to Sf1-Cre mice to induce the expression of FOXL2 in the SF1+ somatic cells of the fetal gonads.When FOXL2 was induced in the somatic cells of the undifferentiated testis, the Sertoli cells and consequently the other cell lineages composing the fetal gonads were feminized, resulting in a partial testis-to-ovary sex reversal We created a mouse genetic model that conditionaly express FOXL2 in the somatic cells of the fetal gonads. All embryos used in this study resulted from the crossing between Rosa26-CAG-LSL-Foxl2+/f and Sf1-cre+/Tg mice. XX and XY fetal gonads were collected at embryonic day E14.5. This microarray analysis led to the identification of the genes misregulated upon ectopic induction of FOXL2 in the fetal testis, and showed that FOXL2 expression resulted in feminization of both somatic and germ cells of the fetal gonad.
Project description:ChIP-on-Chip experiment using chromatin from wild-type 5 weeks old swiss mice ovaries (Nishi et al, 2001) and an isovolumic blend of our custom anti-Foxl2 polyclonal antibodies (Cocquet J et al, 2002). Non precipitated sheared matched deproteinized chromatin (Input) was used a control to estimate genomic enrichment peaks (and thus Foxl2 binding sites) from IPed DNA. DNA from three independent ChIP assays (Input extractions) was pooled, and 100ng of DNA was linearly amplified using the Whole Genome Amplification kit (Sigma).
Project description:FOXL2 is a lineage determining transcription factor in the ovary, but its direct targets and modes of action are not fully characterized. Here, we explore the genomic targets of FOXL2. We found in particular that FOXL2 directly modulates Esr2 expression through a newly identified intronic element. Input DNA and FOXL2 ChIP
Project description:FOXL2 is a lineage determining transcription factor in the ovary, but its direct targets and modes of action are not fully characterized. Here, we explore the genomic targets of FOXL2. We found in particular that FOXL2 directly modulates Esr2 expression through a newly identified intronic element.
Project description:It has previously been shown that FOXL2 and ESR1 cooperate to repress the testis-determining gene Sox9 in murine granulosa cells, and suggested that FOXL2/ESR1 cooperation may be central to granulosa cell differentiation (Uhlenhaut et al., 2009). However, no study has so far compared the DNA-binding of FOXL2 and ESR1 at the genomic level or analyzed the impact of FOXL2 on ESR1 binding to its regulatory elements. Here, we have analyzed and compared the genomic locations recognized by ESR1 and FOXL2 in E2-treated primary murine granulosa cells. Input DNA, FOXL2 and ESR1 ChIP