RNA helicase Brr2a promotes miRNA biogenesis by properly remodelling secondary structure of pri-miRNAs

Nat Plants. 2024 Oct;10(10):1532-1547. doi: 10.1038/s41477-024-01788-8. Epub 2024 Sep 13.

Abstract

RNA secondary structure (RSS) of primary microRNAs (pri-miRNAs) is a key determinant for miRNA production. Here we report that RNA helicase (RH) Brr2a, best known as a spliceosome component, modulates the structural complexity of pri-miRNAs to fine tune miRNA yield. Brr2a interacts with microprocessor component HYL1 and its loss reduces the levels of miRNAs derived from both intron-containing and intron-lacking pri-miRNAs. Brr2a binds to pri-miRNAs in vivo and in vitro. Furthermore, Brr2a hydrolyses ATP and the activity can be significantly enhanced by pri-miRNAs. Consequently, Brr2a unwinds pri-miRNAs in vitro. Moreover, Brr2a variants with compromised ATPase or RH activity are incapable of unwinding pri-miRNA, and their transgenic plants fail to restore miRNA levels in brr2a-2. Importantly, most of tested pri-miRNAs display distinct RSS, rendering them unsuitable for efficient processing in brr2a mutants vs Col-0. Collectively, this study reveals that Brr2a plays a non-canonical role in miRNA production beyond splicing regulation.

Publication types

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

MeSH terms

  • Arabidopsis Proteins* / genetics
  • Arabidopsis Proteins* / metabolism
  • Arabidopsis* / genetics
  • Arabidopsis* / metabolism
  • MicroRNAs* / genetics
  • MicroRNAs* / metabolism
  • Nucleic Acid Conformation
  • RNA Helicases* / genetics
  • RNA Helicases* / metabolism
  • RNA, Plant / genetics
  • RNA, Plant / metabolism

Substances

  • MicroRNAs
  • RNA Helicases
  • Arabidopsis Proteins
  • RNA, Plant