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: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:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility. Gene expression was measured in whole testis from males aged 62-86 days. Samples include 190 first generation lab-bred male offspring of wild-caught mice from the Mus musculus musculus - M. m. domesticus hybrid zone.
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: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:Gonad somatic cells acquire sex-specific fates during sex determination. In XX gonad, a subset of somatic cells expresses Foxl2 after sex determination which are considered as the progenitor of granulosa cells. However, whether these cells also contribute to other cell type at later developmental stage is unknown. In the present study, the cell fate of Foxl2-expressing cells in fetal ovaries was analyzed by lineage tracing and signal-cell transcriptomics. We found that Foxl2-expressing cells gave rise to three cell types at later developmental stage, including granulosa cells, theca-interstitial cells, and stromal cells. Series single-cell RNA sequencing revealed that Foxl2-positive cells were divided into two clusters at P0. One group further differentiated into granulosa cells and theca cells at P14. Another group was classified as stromal cell lineage, then a small portion of them further differentiated into 3β-HSD-positive interstitial cells. We also found that interstitial cells were CYP17a1-positive, whereas theca cells did express this gene. Our data provide an important resource, at single-cell resolution, for better understanding somatic cell differentiation in ovary development.
Project description:Transcription factors related to the insect sex determination gene Doublesex (DMRT proteins) control sex determination and/or sexual differentiation in diverse metazoans. They also are implicated in transitions between sex-determining mechanisms during vertebrate evolution. In mice Dmrt1 is required for male gonadal differentiation in somatic cells and germ cells. DMRT1 also maintains male gonadal sex: its loss, even in adults, can trigger sexual fate reprogramming in which male Sertoli cells transdifferentiate into their female equivalents - granulosa cells - and testicular tissue reorganizes to a more ovarian morphology. Here we use a conditional Dmrt1 transgene to show that Dmrt1 is not only necessary but also sufficient to specify male cell identity in the mouse gonad. DMRT1 expression in the ovary silenced the female sex-maintenance gene Foxl2 and reprogrammed juvenile and adult granulosa cells into Sertoli-like cells, triggering formation of structures resembling male seminiferous tubules. DMRT1 can silence Foxl2 even in the absence of the testis-determining genes Sox8 and Sox9. mRNA profiling found that DMRT1 activates many testicular genes and downregulates ovarian genes and single cell RNA-seq in transdifferentiating cells identified dynamically expressed candidate mediators of this process. Strongly upregulated genes were highly enriched on chromosome X, consistent with sexually antagonistic functions. This study provides an in vivo example of single gene reprogramming of cell sexual identity. Our findings suggest a reconsideration of mechanisms involved in human disorders of sexual development (DSD) and empirically support evolutionary models where loss or gain of Dmrt1 function promotes establishment of new vertebrate sex determination systems. RNA-Seq (3 conditions, 2 replicates per condition) and Single Cell RNA-Seq (68 individual cells and 1 bulk cell sample)