The Aurora B Kinase and the Polycomb Protein Ring1B Combine to Regulate Active Promoters in Quiescent Lymphocytes

• Aurora B and Ring1B co-occupy active promoters in resting lymphocytes
• Loss of Ring1B or Aurora B reduces transcription and binding of RNAPII
• Aurora B enhances binding of USP16 and phosphorylates histone H3S28
• Ubiquitination of H2A by Ring1B is inhibited by phosphorylation of UBE2D3

SummaryReversible cellular quiescence is critical for developmental processes in metazoan organisms and is characterized by a reduction in cell size and transcriptional activity. We show that the Aurora B kinase and the polycomb protein Ring1B have essential roles in regulating transcriptionally active genes in quiescent lymphocytes. Ring1B and Aurora B bind to a wide range of active promoters in resting B and T cells. Conditional knockout of either protein results in reduced transcription and binding of RNA Pol II to promoter regions and decreased cell viability. Aurora B phosphorylates histone H3S28 at active promoters in resting B cells as well as inhibiting Ring1B-mediated ubiquitination of histone H2A and enhancing binding and activity of the USP16 deubiquitinase at transcribed genes. Our results identify a mechanism for regulating transcription in quiescent cells that has implications for epigenetic regulation of the choice between proliferation and quiescence.

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