Department of Biotechnology
inStem (Institute for Stem Cell Science and Regenerative Medicine)

A transcriptionally repressed quiescence program is associated with paused RNA polymerase II and is poised for cell cycle re-entry.

Publication Type

Journal Article

Date of Publication

August 1, 2022

Journal

Journal of cell science

Volume/Issue

135/15

ISSN

1477-9137

Adult stem cells persist in mammalian tissues by entering a state of reversible quiescence, referred to as G0, which is associated with low levels of transcription. Using cultured myoblasts and muscle stem cells, we report that in G0, global RNA content and synthesis are substantially repressed, correlating with decreased RNA polymerase II (RNAPII) expression and activation. Integrating RNAPII occupancy and transcriptome profiling, we identify repressed networks and a role for promoter-proximal RNAPII pausing in G0. Strikingly, RNAPII shows enhanced pausing in G0 on repressed genes encoding regulators of RNA biogenesis (such as Ncl, Rps24, Ctdp1), and release of pausing is associated with increased expression of these genes in G1. Knockdown of these transcripts in proliferating cells leads to induction of G0 markers, confirming the importance of their repression in establishment of G0. A targeted screen of RNAPII regulators revealed that knockdown of Aff4 (a positive regulator of elongation) unexpectedly enhances expression of G0-stalled genes and hastens S phase; however, the negative elongation factor (NELF) complex, a regulator of pausing, appears to be dispensable. We propose that RNAPII pausing contributes to transcriptional control of a subset of G0-repressed genes to maintain quiescence and impacts the timing of the G0-G1 transition. This article has an associated First Person interview with the first authors of the paper.

Alternate Journal

J Cell Sci

PubMed ID

35781573

Authors

Hardik P Gala
Debarya Saha
Nisha Venugopal
Ajoy Aloysius
Gunjan Purohit
Jyotsna Dhawan

Keywords

RNA
Cell Cycle
Gene Expression Regulation
RNA Polymerase II
Transcription, Genetic
Transcriptional Elongation Factors
Animals
Promoter Regions, Genetic
Mammals