Analysis of the Epigenomic and Transcriptional Landscapes during mammalian spermatogenesis [ChIP-seq]

Adult germline stem cells (AGSCs) are multifunctional - they must self renew, maintain genome pluripotency, and prepare for gametogenesis – which involves meiotic and chromatin repackaging phases. To better understand AGSCs and gametogenesis, we derived high-resolution profiles of transcription, DNA methylation, 5hmC, and multiple histone modifications at key stages. First, AGSCs display chromatin ‘poising’ of enhancers and promoters of genes utilized in embryo development. Second, the pluripotency network in AGSCs is remarkably distinct from ESCs - lacking Nanog, Sox2, or Prdm14 expression.  Third, spermatogenesis involves stage-specific transcription and distinctive chromatin dynamics, but virtually no changes in DNAme.  Surprisingly, we observe co-incidence of RNA polymerase II, high H3K4me3, and DNA methylation at 20-35% of genes transcribed during gametogenesis - including piRNA clusters - but often observe attendant promoter 5hmC.  Our work reveals key differences between AGSCs and other germ/stem cells, and reveals both logical and unexpected chromatin-transcription relationships accompanying germline developmental transitions. Examination of 7 different histone modifications and 5hMC in 4 different cell types