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.

2022-09-06 | GSE163960 | GEO

OCT4-SOX2 dimers reshape the epigenome to promote neural crest multipotency [ATAC-Seq]

2022-09-06 | GSE163771 | GEO

tfGorAlbo

Project description:Gordius_albopunctatus, genomic and transcriptomic data

| PRJEB78907 | ENA

Heterodimerization of Tfap2 pioneer factors drives epigenomic remodeling during neural crest specification

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.

2019-12-12 | GSE126880 | GEO

Tropheryma whipplei proteome - Analyses of new genomic, transcriptomic or proteomic data commonly result in trashing many unidentified data escaping the ‘canonical’ DNA-RNA-protein scheme

Project description:Analyses of new genomic, transcriptomic or proteomic data commonly result in trashing many unidentified data escaping the ‘canonical’ DNA-RNA-protein scheme. Testing systematic exchanges of nucleotides over long stretches produces inversed RNA pieces (here named “swinger” RNA) differing from their template DNA. These may explain some trashed data. Here analyses of genomic, transcriptomic and proteomic data of the pathogenic Tropheryma whipplei according to canonical genomic, transcriptomic and translational 'rules' resulted in trashing 58.9% of DNA, 37.7% RNA and about 85% of mass spectra (corresponding to peptides). In the trash, we found numerous DNA/RNA fragments compatible with “swinger” polymerization. Genomic sequences covered by «swinger» DNA and RNA are 3X more frequent than expected by chance and explained 12.4 and 20.8% of the rejected DNA and RNA sequences, respectively. As for peptides, several match with “swinger” RNAs, including some chimera, translated from both regular, and «swinger» transcripts, notably for ribosomal RNAs. Congruence of DNA, RNA and peptides resulting from the same swinging process suggest that systematic nucleotide exchanges increase coding potential, and may add to evolutionary diversification of bacterial populations.

2017-12-18 | PXD006238 | Pride