Tissue-specific TAFs counteract Polycomb to turn on terminal differentiation.
Polycomb transcriptional silencing machinery is implicated in the maintenance of precursor fates, but how this repression is reversed to allow cell differentiation is unknown. Here we show that testis-specific TAF (TBP-associated factor) homologs required for terminal differentiation of male germ cells may activate target gene expression in part by counteracting repression by Polycomb. Chromatin immunoprecipitation revealed that testis TAFs bind to target promoters, reduce Polycomb binding, and promote local accumulation of H3K4me3, a mark of Trithorax action. Testis TAFs also promoted relocalization of Polycomb Repression Complex 1 components to the nucleolus in spermatocytes, implicating subnuclear architecture in the regulation of terminal differentiation.
Chen
Xin
X
Departments of Developmental Biology and Genetics, Stanford University School of Medicine, Stanford, CA 94305-5329, USA.
Hiller
Mark
M
Sancak
Yasemin
Y
Fuller
Margaret T
MT
D000818:Animals; D002454:Cell Differentiation; D002466:Cell Nucleolus / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D004330:Drosophila / Q000166:cytology* / Q000235:genetics / Q000502:physiology; D029721:Drosophila Proteins / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D008297:Male; D063150:Polycomb Repressive Complex 1; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013090:Spermatocytes / Q000166:cytology* / Q000378:metabolism*; D013091:Spermatogenesis; D035381:TATA-Binding Protein Associated Factors / Q000378:metabolism*; D013737:Testis / Q000378:metabolism; D014158:Transcription, Genetic
D029721:Drosophila Proteins; C066770:Pc protein, Drosophila; D011993:Recombinant Fusion Proteins; D035381:TATA-Binding Protein Associated Factors; D063150:Polycomb Repressive Complex 1