Project description:When stem cells activate a member of the SOX family of pioneer factors, they bind their cognate sequences within condensed chromatin, not only evicting the associated nucleosome, but also recruiting H3K4-monomethylases, which modify flanking nucleosomes to open chromatin and activate one lineage program; simultaneously, pioneer factors also silence alternative fates, but in this case act indirectly, through competing for H3K4-monomethylases pre-existing at the original fate genes.
Project description:When stem cells activate a member of the SOX family of pioneer factors, they bind their cognate sequences within condensed chromatin, not only evicting the associated nucleosome, but also recruiting H3K4-monomethylases, which modify flanking nucleosomes to open chromatin and activate one lineage program; simultaneously, pioneer factors also silence alternative fates, but in this case act indirectly, through competing for H3K4-monomethylases pre-existing at the original fate genes.
Project description:When stem cells activate a member of the SOX family of pioneer factors, they bind their cognate sequences within condensed chromatin, not only evicting the associated nucleosome, but also recruiting H3K4-monomethylases, which modify flanking nucleosomes to open chromatin and activate one lineage program; simultaneously, pioneer factors also silence alternative fates, but in this case act indirectly, through competing for H3K4-monomethylases pre-existing at the original fate genes.
Project description:When stem cells activate a member of the SOX family of pioneer factors, they bind their cognate sequences within condensed chromatin, not only evicting the associated nucleosome, but also recruiting H3K4-monomethylases, which modify flanking nucleosomes to open chromatin and activate one lineage program; simultaneously, pioneer factors also silence alternative fates, but in this case act indirectly, through competing for H3K4-monomethylases pre-existing at the original fate genes.
Project description:Mammalian sexual development commences when fetal bipotential progenitor cells adopt male Sertoli (in XY) or female granulosa (in XX) gonadal cell fates. Differentiation of these cells involves extensive divergence in chromatin state and gene expression, reflecting distinct roles in sexual differentiation and gametogenesis. Surprisingly, differentiated gonadal cell fates require active maintenance through postnatal life to prevent sexual transdifferentiation and female cell fate can be reprogrammed by ectopic expression of the sex regulator DMRT1. Here we examine how DMRT1 reprograms granulosa cells to Sertoli-like cells in vivo and in culture. We define postnatal granulosa- and Sertoli-biased gene expression programs and identify cell type-biased three-dimensional chromatin contacts and differentially accessible chromatin regions (DARs) associated with differentially expressed genes. Using a conditional transgene we find DMRT1 only partially reprograms the ovarian transcriptome in the absence of SOX9 and its paralog SOX8, indicating that these factors functionally cooperate with DMRT1. ATAC-seq and ChIP-seq show that DMRT1 induces formation of many DARs that it binds with SOX9, and DMRT1 is required for binding of SOX9 at most of these sites. We suggest that DMRT1 can act as a pioneer factor to open chromatin and allow binding of SOX9, which then cooperates with DMRT1 to reprogram sexual cell fate.