Active retrotransposons help maintain pericentromeric heterochromatin required for faithful cell division

  1. Shunmin He1,2
  1. 1Key Laboratory of RNA Biology, Center for Big Data Research in Health, Institute of Biophysics, Chinese Academy of Sciences, 100101, China;
  2. 2University of Chinese Academy of Sciences, Beijing, 100049, China;
  3. 3Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093-0651, USA;
  4. 4Guangdong Geneway Decoding Bio-Tech Corporation Limited, Foshan 528316, China
  1. 5 These authors contributed equally to this work.

  • Corresponding authors: xdfu{at}ucsd.edu, chenrs{at}sun5.ibp.ac.cn, heshunmin{at}ibp.ac.cn
  • Abstract

    Retrotransposons are populated in vertebrate genomes, and when active, are thought to cause genome instability with potential benefit to genome evolution. Retrotransposon-derived RNAs are also known to give rise to small endo-siRNAs to help maintain heterochromatin at their sites of transcription; however, as not all heterochromatic regions are equally active in transcription, it remains unclear how heterochromatin is maintained across the genome. Here, we address these problems by defining the origins of repeat-derived RNAs and their specific chromatin locations in Drosophila S2 cells. We demonstrate that repeat RNAs are predominantly derived from active gypsy elements and processed by Dcr-2 into small RNAs to help maintain pericentromeric heterochromatin. We also show in cultured S2 cells that synthetic repeat-derived endo-siRNA mimics are sufficient to rescue Dcr-2-deficiency-induced defects in heterochromatin formation in interphase and chromosome segregation during mitosis, demonstrating that active retrotransposons are required for stable genetic inheritance.

    Footnotes

    • Received August 19, 2019.
    • Accepted September 22, 2020.

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