Maelstrom Represses Canonical Polymerase II Transcription within Bi-directional piRNA Clusters in Drosophila melanogaster
RNA Therapeutics Institute; Program in Bioinformatics and Integrative Biology; Department of Biochemistry and Molecular Pharmacology; Graduate School of Biomedical Sciences
Amino Acids, Peptides, and Proteins | Biochemistry | Bioinformatics | Computational Biology | Genetics and Genomics | Molecular Biology | Nucleic Acids, Nucleotides, and Nucleosides
In Drosophila, 23-30 nt long PIWI-interacting RNAs (piRNAs) direct the protein Piwi to silence germline transposon transcription. Most germline piRNAs derive from dual-strand piRNA clusters, heterochromatic transposon graveyards that are transcribed from both genomic strands. These piRNA sources are marked by the heterochromatin protein 1 homolog Rhino (Rhi), which facilitates their promoter-independent transcription, suppresses splicing, and inhibits transcriptional termination. Here, we report that the protein Maelstrom (Mael) represses canonical, promoter-dependent transcription in dual-strand clusters, allowing Rhi to initiate piRNA precursor transcription. Mael also represses promoter-dependent transcription at sites outside clusters. At some loci, Mael repression requires the piRNA pathway, while at others, piRNAs play no role. We propose that by repressing canonical transcription of individual transposon mRNAs, Mael helps Rhi drive non-canonical transcription of piRNA precursors without generating mRNAs encoding transposon proteins.
Argonaute, Armitage, Maelstrom, PIWI-interacting RNA, Piwi, Rhino, piRNA, small silencing RNA, transcription, transposon
DOI of Published Version
Mol Cell. 2018 Nov 12. pii: S1097-2765(18)30932-8. doi: 10.1016/j.molcel.2018.10.038. [Epub ahead of print]. Link to article on publisher's site
Chang, Timothy; Mattei, Eugenio; Ildar Gainetdinov; Colpan, Cansu; Weng, Zhiping; and Zamore, Phillip D., "Maelstrom Represses Canonical Polymerase II Transcription within Bi-directional piRNA Clusters in Drosophila melanogaster" (2018). Program in Bioinformatics and Integrative Biology Publications and Presentations. 142.