NOVA2 regulates neural circRNA biogenesis

Nucleic Acids Res. 2021 Jul 9;49(12):6849-6862. doi: 10.1093/nar/gkab523.

Abstract

Circular RNAs (circRNAs) are highly expressed in the brain and their expression increases during neuronal differentiation. The factors regulating circRNAs in the developing mouse brain are unknown. NOVA1 and NOVA2 are neural-enriched RNA-binding proteins with well-characterized roles in alternative splicing. Profiling of circRNAs from RNA-seq data revealed that global circRNA levels were reduced in embryonic cortex of Nova2 but not Nova1 knockout mice. Analysis of isolated inhibitory and excitatory cortical neurons lacking NOVA2 revealed an even more dramatic reduction of circRNAs and establishes a widespread role for NOVA2 in enhancing circRNA biogenesis. To investigate the cis-elements controlling NOVA2-regulation of circRNA biogenesis, we generated a backsplicing reporter based on the Efnb2 gene. We found that NOVA2-mediated backsplicing of circEfnb2 was impaired when YCAY clusters located in flanking introns were mutagenized. CLIP (cross-linking and immunoprecipitation) and additional reporter analyses demonstrated the importance of NOVA2 binding sites located in both flanking introns of circRNA loci. NOVA2 is the first RNA-binding protein identified to globally promote circRNA biogenesis in the developing brain.

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

  • Alternative Splicing
  • Animals
  • Antigens, Neoplasm / genetics
  • Antigens, Neoplasm / metabolism
  • Antigens, Neoplasm / physiology*
  • Binding Sites
  • Brain / embryology
  • Brain / metabolism*
  • Ephrin-B2 / genetics
  • Exons
  • Gene Expression Regulation
  • HEK293 Cells
  • Humans
  • Introns
  • Mice
  • Mice, Knockout
  • Neuro-Oncological Ventral Antigen
  • Neurons / metabolism*
  • Nucleotide Motifs
  • RNA, Circular / chemistry
  • RNA, Circular / metabolism*
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism
  • RNA-Binding Proteins / physiology*

Substances

  • Antigens, Neoplasm
  • EFNB2 protein, mouse
  • Ephrin-B2
  • Neuro-Oncological Ventral Antigen
  • Nova1 protein, mouse
  • Nova2 protein, mouse
  • RNA, Circular
  • RNA-Binding Proteins