A Sex Chromosome piRNA Promotes Robust Dosage Compensation and Sex Determination in C. elegans

Dev Cell. 2018 Mar 26;44(6):762-770.e3. doi: 10.1016/j.devcel.2018.01.025. Epub 2018 Feb 15.

Abstract

In metazoans, Piwi-related Argonaute proteins engage piRNAs (Piwi-interacting small RNAs) to defend the genome against invasive nucleic acids, such as transposable elements. Yet many organisms-including worms and humans-express thousands of piRNAs that do not target transposons, suggesting that piRNA function extends beyond genome defense. Here, we show that the X chromosome-derived piRNA 21ux-1 downregulates XOL-1 (XO Lethal), a master regulator of X chromosome dosage compensation and sex determination in Caenorhabditis elegans. Mutations in 21ux-1 and several Piwi-pathway components sensitize hermaphrodites to dosage compensation and sex determination defects. We show that the piRNA pathway also targets xol-1 in C. briggsae, a nematode species related to C. elegans. Our findings reveal physiologically important piRNA-mRNA interactions, raising the possibility that piRNAs function broadly to ensure robust gene expression and germline development.

Keywords: Caenorhabditis briggsae; Caenorhabditis elegans; dosage compensation; piRNAs; sex determination; small RNAs.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Dosage Compensation, Genetic*
  • Gene Expression Regulation*
  • Phenotype
  • RNA, Small Interfering / genetics*
  • Sex Chromosomes*
  • Sex Determination Analysis*

Substances

  • Caenorhabditis elegans Proteins
  • RNA, Small Interfering