AI Article Synopsis
- Transcriptional silencing in yeast occurs at key sites like mating-type loci, telomeres, and ribosomal DNA, marked by a lack of histone modifications.
- Sir2, an essential enzyme for silencing, along with other Sir proteins, forms a structure known as silent chromatin that is crucial for gene regulation.
- Research over the past 25 years has provided insights into how this silencing is established, maintained, and inherited, impacting our understanding of gene expression and cell aging.
Article Abstract
Transcriptional silencing in Saccharomyces cerevisiae occurs at several genomic sites including the silent mating-type loci, telomeres, and the ribosomal DNA (rDNA) tandem array. Epigenetic silencing at each of these domains is characterized by the absence of nearly all histone modifications, including most prominently the lack of histone H4 lysine 16 acetylation. In all cases, silencing requires Sir2, a highly-conserved NAD(+)-dependent histone deacetylase. At locations other than the rDNA, silencing also requires additional Sir proteins, Sir1, Sir3, and Sir4 that together form a repressive heterochromatin-like structure termed silent chromatin. The mechanisms of silent chromatin establishment, maintenance, and inheritance have been investigated extensively over the last 25 years, and these studies have revealed numerous paradigms for transcriptional repression, chromatin organization, and epigenetic gene regulation. Studies of Sir2-dependent silencing at the rDNA have also contributed to understanding the mechanisms for maintaining the stability of repetitive DNA and regulating replicative cell aging. The goal of this comprehensive review is to distill a wide array of biochemical, molecular genetic, cell biological, and genomics studies down to the "nuts and bolts" of silent chromatin and the processes that yield transcriptional silencing.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4981263 | PMC |
| http://dx.doi.org/10.1534/genetics.112.145243 | DOI Listing |
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