Sir2 is required for the quiescence-specific condensed three-dimensional chromatin structure of rDNA.

ABSTRACT: Quiescence in Saccharomyces cerevisiae is a reversible G₀ crucial for long-term survival under nutrient-deprived conditions. During quiescence, the genome is hypoacetylated and chromatin undergoes significant compaction. However, the 3D structure of the ribosomal DNA (rDNA) locus in this state is not well understood. Here, we report that the rDNA locus in quiescent cells forms a distinct condensed loop-like structure, different from structures observed during the mitotic cell cycle. Deletion of SIR2 disrupts this structure, causing it to collapse into a small dot and resulting in quiescence entry and exit defects. In contrast, Sir2 affects rDNA structure only modestly in G2/M phase. In the absence of Sir2, occupancy of both RNA Polymerase II and histone H3 increase

SUBMITTER: Cucinotta C 

PROVIDER: S-EPMC11661206 | biostudies-literature | 2024 Dec

REPOSITORIES: biostudies-literature