Genome-wide maps of chromatin structure in wild-type and nanos mutant primordial germ cells in C. elegans

The Nanos family of RNA-binding proteins has been implicated in the specification of primordial germ cells (PGCs) in a wide range of metazoans, but the underlying mechanisms remain poorly understood. We have profiled the transcriptome of PGCs lacking the nanos homologues nos-1 and nos-2 in C. elegans using cell sorting and RNA-seq. nos-1nos-2 PGCs fail to silence hundreds of genes normally expressed in oocytes and somatic cells, a phenotype reminiscent of PGCs lacking the repressive PRC2 complex. The nos-1nos-2 phenotype depends on LIN-15B, a broadly expressed synMuvB class transcription factor known to antagonize PRC2 activity in somatic cells. LIN-15B is maternally-inherited by all embryonic cells and is down-regulated specifically in PGCs in a nos-1nos-2-dependent manner. Consistent with LIN-15B being a critical target of Nanos regulation, inactivation of maternal LIN-15B restores fertility to nos-1nos-2 mutants. These studies demonstrate a central role for Nanos in reprogramming the transcriptome of primordial germ cells away from an oocyte/somatic fate by down-regulating an antagonist of PRC2 activity. 4 biological ATAC-seq samples are included in this study. These include two biological samples from wild-type and two biological samples from nos-1 nos-2 mutant PGCs