2026-04-14T02:47:36Zhttps://recercat.cat/oai/request

oai:recercat.cat:10230/427522025-12-22T13:37:13Zcom_2072_6col_2072_452952

00925njm 22002777a 4500 dc González Medina, Alberto, 1990- author Hidalgo Hernando, Elena author Ayté del Olmo, José author 2019-11-06T10:51:36Z 2019-11-06T10:51:36Z 2019 In fission yeast, MBF-dependent transcription is inactivated at the end of S phase through a negative feedback loop that involves the co-repressors, Yox1 and Nrm1. Although this repression system is well known, the molecular mechanisms involved in MBF activation remain largely unknown. Compacted chromatin constitutes a barrier to activators accessing promoters. Here, we show that chromatin regulation plays a key role in activating MBF-dependent transcription. Gcn5, a part of the SAGA complex, binds to MBF-regulated promoters through the MBF co-activator Rep2 in a cell cycle-dependent manner and in a reverse correlation to the binding of the MBF co-repressors, Nrm1 or Yox1. We propose that the co-repressors function as physical barriers to SAGA recruitment onto MBF promoters. We also show that Gcn5 acetylates specific lysine residues on histone H3 in a cell cycle-regulated manner. Furthermore, either in a gcn5 mutant or in a strain in which histone H3 is kept in an unacetylated form, MBF-dependent transcription is downregulated. In summary, Gcn5 is required for the full activation and correct timing of MBF-regulated gene transcription. Spanish Ministerio de Economia y Competitividad, PLAN E, and Feder [BFU2015-66347, PGC2018-097248-B-I00]; MEIONet [BFU2015-71786-REDT]; Unidad de Excelencia Maria de Maeztu [MDM-2014-0370]; ICREA Academia Award (Generalitat de Catalunya) (to E.H.). Funding for open access charge: Spanish Ministerio de Economia y Competitividad [BFU2015-66347, PGC2018-097248-B-I00]. Gene regulation Chromatin and epigenetics Gcn5-mediated acetylation at MBF-regulated promoters induces the G1/S transcriptional wave