| Adipocytic cell fate determination and differentiation requires tight regulation of gene expression programs. These regulatory circuitries are a balanced act between positively induced transcriptional cascades required for a specific cell fate and counteracting regulatory transcription factors which favor undifferentiated cell states or alternative cell fates. Although many individual players in late adipocytic differentiation are known, the interplay of these factors and their interactions with specific or shared target genes are still largely unknown. More importantly, initial factors which determine adipocytic cell fate have not been identified. In this proposal, we plan to investigate genome wide spatial and temporal DNA accessibility during early and late adipocytic cell differentiation to profile potential regulatory sites. Proteins binding to these sites will be predicted based on underlying motifs and determined in DNA-protein interaction screens. A very recently developed technique ChIA-PET will provide genome-wide maps of short- and long-range interactions between regulatory elements and their target genes during adipocytic differentiation. Known factors in adipocytic differentiation such as PPARgamma and CEBPs and general (co)factors that are required for transcription in all phases of differentiation such as TFIIB and p300 will be used as anchor proteins to link regulated target genes with regulatory elements at accessible sites. This integrative approach will reveal not only the complex transcriptional networks orchestrating adipocytic differentiation but also the novel factors that determine adipocytic cell fate. These novel factors will be tested in bi and multi potent progenitor stem cell systems to establish their functional role in adipocytic cell fate determination. |
