Rap1 relocalization contributes to the chromatin-mediated gene expression profile and pace of cell senescence.

TitleRap1 relocalization contributes to the chromatin-mediated gene expression profile and pace of cell senescence.
Publication TypeJournal Article
Year of Publication2013
AuthorsPlatt JM, Ryvkin P, Wanat JJ, Donahue G, M Ricketts D, Barrett SP, Waters HJ, Song S, Chavez A, Abdallah KOmar, Master SR, San Wang L-, F Johnson B
JournalGenes Dev
Volume27
Issue12
Pagination1406-20
Date Published2013 Jun 15
ISSN1549-5477
KeywordsChromatin, Gene Expression Regulation, Fungal, Histones, Microbial Viability, Protein Transport, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Shelterin Complex, Telomere, Telomere-Binding Proteins, Transcription Factors, Transcriptome
Abstract

Cellular senescence is accompanied by dramatic changes in chromatin structure and gene expression. Using Saccharomyces cerevisiae mutants lacking telomerase (tlc1Δ) to model senescence, we found that with critical telomere shortening, the telomere-binding protein Rap1 (repressor activator protein 1) relocalizes to the upstream promoter regions of hundreds of new target genes. The set of new Rap1 targets at senescence (NRTS) is preferentially activated at senescence, and experimental manipulations of Rap1 levels indicate that it contributes directly to NRTS activation. A notable subset of NRTS includes the core histone-encoding genes; we found that Rap1 contributes to their repression and that histone protein levels decline at senescence. Rap1 and histones also display a target site-specific antagonism that leads to diminished nucleosome occupancy at the promoters of up-regulated NRTS. This antagonism apparently impacts the rate of senescence because underexpression of Rap1 or overexpression of the core histones delays senescence. Rap1 relocalization is not a simple consequence of lost telomere-binding sites, but rather depends on the Mec1 checkpoint kinase. Rap1 relocalization is thus a novel mechanism connecting DNA damage responses (DDRs) at telomeres to global changes in chromatin and gene expression while driving the pace of senescence.

DOI10.1101/gad.218776.113
Alternate JournalGenes Dev
PubMed ID23756653
PubMed Central IDPMC3701195
Grant ListT32-HG000046 / HG / NHGRI NIH HHS / United States
P01-AG031862 / AG / NIA NIH HHS / United States
P01 AG031862 / AG / NIA NIH HHS / United States
R01-AG021521 / AG / NIA NIH HHS / United States
T32 HG000046 / HG / NHGRI NIH HHS / United States
R01 AG021521 / AG / NIA NIH HHS / United States
T32 AG000255 / AG / NIA NIH HHS / United States
T32-AG000255 / AG / NIA NIH HHS / United States