Acetyltransferase Enok regulates transposon silencing by promoting transcription at piRNA clusters and genes involved in piRNA biosynthesis [H3 and H3K23 ChIP-seq]

ABSTRACT: The PIWI-interacting RNA (piRNA) pathway is an important mechanism to suppress transposon activation in the germline that is highly conserved between Drosophila and mammals. This pathway starts from transcribing piRNA clusters to generate long piRNA precursors. The majority of piRNA clusters lacks a conventional promoter, and therefore their transcription is considered to utilize a noncanonical mechanism. However, information regarding transcriptional regulation of piRNA clusters is limited. Here, we report that the fly KAT6 acetyltransferase, Enok, is important for transposon silencing in the germline. Further small RNA-seq analysis revealed that Enok is critical for piRNA production from a specific subset of piRNA clusters including 42AB, one of the two major sources of piRNAs. Enok is the major enzyme for establishing the H3K23ac mark, and was shown to promote gene expression by acetylating H3K23. Surprisingly, our RNA-seq and ChIP-seq/ChIP-qPCR results suggest that Enok regulates expression of genes involved in the piRNA production by H3K23ac-dependent mechanisms, and also promotes transcription at piRNA clusters through H3K23ac-independent pathways. Our co-immunoprecipitation assay further suggests that Enok interacts with RNA polymerase II to facilitate transcription of piRNA clusters. Taken together, our study provides novel insights into the regulation of noncanonical transcription at piRNA clusters and transposon silencing.

ORGANISM(S): Drosophila melanogaster

PROVIDER: GSE154839 | GEO | 2021/01/07

REPOSITORIES: GEO