The Upstream Sequence Transcription Complex Dictates Nucleosome Positioning and Promoter Accessibility at piRNA Genes in the C. elegans Germ Line.

ABSTRACT: The piRNA pathway is a conserved germline-specific small RNA pathway that ensures genomic integrity and continued fertility. In C. elegans and other nematodes, Type-I piRNA precursor transcripts are expressed from over 10,000 small, independently regulated genes clustered within two discrete domains of 1.5 and 3.5 MB on Chromosome IV. These large clusters likely play a significant role in promoting germline-specific expression of piRNAs, but the underlying mechanisms are unclear. By examining the chromatin environment specifically in isolated germ nuclei, we demonstrate that piRNA clusters are located in closed chromatin, and confirm the enrichment for the inactive histone modification H3K27me3. We further show that the piRNA biogenesis factor USTC (Upstream Sequence Transcription C

SUBMITTER: Sanchez N 

PROVIDER: S-EPMC10197682 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature