Project description:The transcription factors OCT4 and SOX2 play an essential role in the establishment and maintenance of pluripotent embryonic stem cells (ESCs). Yet, their function in specialized stem cell populations is still poorly understood. Here, we show that the OCT4 and SOX2 work as dimers to regulate the epigenomic landscape of neural crest cells. By isolating primary neural crest cells at a range of developmental stages, we characterized the transcriptomic and epigenomic changes that take place during specification, migration, and early differentiation. Analysis of these datasets revealed that the OCT4/SOX2 dimer promotes an epigenomic signature inherent to the multipotent neural crest. We found that the emergence of this epigenomic state requires the translocation of OCT4/SOX2 to tissue-specific cis-regulatory regions. By examining genome organization during the induction of hESCs into neural crest cells, we observed that the patterns of genomic occupancy of the dimer are modified during cell fate commitment. Dimer translocation is guided by neural crest-specific pioneer transcription factors, which physically interact with the OCT4/SOX to modify their genomic targets. Our results demonstrate how the ESC pluripotency program is repurposed in specialized stem cells to control chromatin organization and define the developmental potential of embryonic progenitors.
Project description:The transcription factors OCT4 and SOX2 play an essential role in the establishment and maintenance of pluripotent embryonic stem cells (ESCs). Yet, their function in specialized stem cell populations is still poorly understood. Here, we show that the OCT4 and SOX2 work as dimers to regulate the epigenomic landscape of neural crest cells. By isolating primary neural crest cells at a range of developmental stages, we characterized the transcriptomic and epigenomic changes that take place during specification, migration, and early differentiation. Analysis of these datasets revealed that the OCT4/SOX2 dimer promotes an epigenomic signature inherent to the multipotent neural crest. We found that the emergence of this epigenomic state requires the translocation of OCT4/SOX2 to tissue-specific cis-regulatory regions. By examining genome organization during the induction of hESCs into neural crest cells, we observed that the patterns of genomic occupancy of the dimer are modified during cell fate commitment. Dimer translocation is guided by neural crest-specific pioneer transcription factors, which physically interact with the OCT4/SOX to modify their genomic targets. Our results demonstrate how the ESC pluripotency program is repurposed in specialized stem cells to control chromatin organization and define the developmental potential of embryonic progenitors.
Project description:Cell fate commitment is a stepwise process, in which multipotent progenitors transition through sequential regulatory states as they become fate restricted. Recent studies have highlighted the extensive transcriptomic shifts that typify cell differentiation, but our understanding of the epigenetic mechanisms underlying these changes is still superficial. To examine how chromatin states are reorganized during cell fate commitment in an in vivo system, we examined the function of pioneer factor Tfap2a at discrete stages of neural crest development. Our results show that TFAP2a activates distinct sets of genomic regions during induction and specification of neural crest cells. Genomic occupancy analysis revealed that the repertoire of TFAP2a targets depends upon its dimerization with paralogous proteins TFAP2c and TFAP2b. During gastrula stages, TFAP2a/c heterodimers activate components of the neural plate border induction program. As neurulation begins, TFAP2a trades partners, and TFAP2a/b heterodimers reorganize the epigenomic landscape of progenitor cells to promote neural crest specification. We propose that this molecular switch acts to drive progressive cell commitment, remodeling the epigenomic landscape to define the presumptive neural crest. Our findings show how pioneer factors regulate distinct genomic targets in a stage-specific manner, and highlight how paralogy can serve as an evolutionary strategy to diversify the function of the regulators that control embryonic development.
Project description:The transcription factors OCT4 and SOX2 play an essential role in the establishment and maintenance of pluripotent embryonic stem cells (ESCs). Yet, their function in specialized stem cell populations is still poorly understood. Here, we show that the OCT4 and SOX2 work as dimers to regulate the epigenomic landscape of neural crest cells. By isolating primary neural crest cells at a range of developmental stages, we characterized the transcriptomic and epigenomic changes that take place during specification, migration, and early differentiation. Analysis of these datasets revealed that the OCT4/SOX2 dimer promotes an epigenomic signature inherent to the multipotent neural crest. We found that the emergence of this epigenomic state requires the translocation of OCT4/SOX2 to tissue-specific cis-regulatory regions. By examining genome organization during the induction of hESCs into neural crest cells, we observed that the patterns of genomic occupancy of the dimer are modified during cell fate commitment. Dimer translocation is guided by neural crest-specific pioneer transcription factors, which physically interact with the OCT4/SOX to modify their genomic targets. Our results demonstrate how the ESC pluripotency program is repurposed in specialized stem cells to control chromatin organization and define the developmental potential of embryonic progenitors.
Project description:The transcription factors OCT4 and SOX2 play an essential role in the establishment and maintenance of pluripotent embryonic stem cells (ESCs). Yet, their function in specialized stem cell populations is still poorly understood. Here, we show that the OCT4 and SOX2 work as dimers to regulate the epigenomic landscape of neural crest cells. By isolating primary neural crest cells at a range of developmental stages, we characterized the transcriptomic and epigenomic changes that take place during specification, migration, and early differentiation. Analysis of these datasets revealed that the OCT4/SOX2 dimer promotes an epigenomic signature inherent to the multipotent neural crest. We found that the emergence of this epigenomic state requires the translocation of OCT4/SOX2 to tissue-specific cis-regulatory regions. By examining genome organization during the induction of hESCs into neural crest cells, we observed that the patterns of genomic occupancy of the dimer are modified during cell fate commitment. Dimer translocation is guided by neural crest-specific pioneer transcription factors, which physically interact with the OCT4/SOX to modify their genomic targets. Our results demonstrate how the ESC pluripotency program is repurposed in specialized stem cells to control chromatin organization and define the developmental potential of embryonic progenitors.