Nuclear microRNAs release paused Pol II via the DDX21-CDK9 complex

Cell Rep. 2022 Apr 12;39(2):110673. doi: 10.1016/j.celrep.2022.110673.

Abstract

RNA activation (RNAa) is an uncharacterized mechanism of transcriptional activation mediated by small RNAs, such as microRNAs (miRNAs). A critical issue in RNAa research is that it is difficult to distinguish between changes in gene expression caused indirectly by post-transcriptional regulation and direct induction of gene expression by RNAa. Therefore, in this study, we seek to identify a key factor involved in RNAa, using the induction of ZMYND10 by miR-34a as a system to evaluate RNAa. We identify the positive transcription elongation factors CDK9 and DDX21, which form a complex with nuclear AGO and TNRC6A, as important transcriptional activators of RNAa. In addition, we find that inhibition of DDX21 suppresses RNAa by miR-34a and other miRNAs without inhibiting post-transcriptional regulation. Our findings reveal a strong connection between RNAa and release of paused Pol II, facilitating RNAa research by making it possible to separately analyze post-transcriptional regulation and RNAa.

Keywords: CDK9; CP: Molecular biology; DDX21; RNA activation; ZMYND10; divergent transcription; miR-34; microRNA; promoter-associated noncoding RNA; small activating RNA.

MeSH terms

  • Cell Nucleus / metabolism
  • Cyclin-Dependent Kinase 9* / metabolism
  • DEAD-box RNA Helicases* / metabolism
  • Gene Expression Regulation
  • MicroRNAs* / genetics
  • RNA Polymerase II* / metabolism
  • Transcriptional Activation

Substances

  • MicroRNAs
  • Cyclin-Dependent Kinase 9
  • RNA Polymerase II
  • DEAD-box RNA Helicases