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Refined mechanism of promoter Nucleosome-Depleted Regions resetting after replication

ABSTRACT: Replication disrupts chromatin organization. Thus, rapid resetting of nucleosome positioning is essential to maintain faithful gene expression. The initial step of this reconfiguration occurs at Nucleosome-Depleted Regions (NDRs). While studies have elucidated the role of Transcription Factors (TFs) and Chromatin Remodelers (CRs) in vitro or in maintaining NDRs in vivo, none has addressed their in vivo function shortly after replication. Through purification of nascent chromatin coupled with yeast genetics, we dissected the choreography of events governing the proper positioning of the -1/+1 nucleosomes flanking promoter NDRs. Our findings reveal that CRs are the primary contributors of -1/+1 repositioning post-replication, with RSC acting upstream of INO80. Surprisingly, while Reb1 and Abf1 TFs are not essential for NDR resetting, they are required for NDR maintenance via the promotion of H3 acetylations. Taken together, we propose a two-step model for NDR resetting in S. cerevisiae: first, CRs alone reset promoter NDRs after replication, while a combination of TFs and CRs is required for subsequent maintenance.

ORGANISM(S): Saccharomyces cerevisiae

PROVIDER: GSE262171 | GEO | 2024/03/25

REPOSITORIES: GEO

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