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DNA Instability Maintains the Repeat Length of the Yeast RNA Polymerase II C-terminal Domain
The C-terminal domain (CTD) of RNA polymerase II in eukaryotes is comprised of tandemly repeating units of a conserved seven-amino acid sequence. The number of repeats is, however, quite variable across different organisms. Furthermore, previous studies have identified evidence of rearrangements wit...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Biochemistry and Molecular Biology
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4882425/ https://www.ncbi.nlm.nih.gov/pubmed/27026700 http://dx.doi.org/10.1074/jbc.M115.696252 |
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author | Morrill, Summer A. Exner, Alexandra E. Babokhov, Michael Reinfeld, Bradley I. Fuchs, Stephen M. |
author_facet | Morrill, Summer A. Exner, Alexandra E. Babokhov, Michael Reinfeld, Bradley I. Fuchs, Stephen M. |
author_sort | Morrill, Summer A. |
collection | PubMed |
description | The C-terminal domain (CTD) of RNA polymerase II in eukaryotes is comprised of tandemly repeating units of a conserved seven-amino acid sequence. The number of repeats is, however, quite variable across different organisms. Furthermore, previous studies have identified evidence of rearrangements within the CTD coding region, suggesting that DNA instability may play a role in regulating or maintaining CTD repeat number. The work described here establishes a clear connection between DNA instability and CTD repeat number in Saccharomyces cerevisiae. First, analysis of 36 diverse S. cerevisiae isolates revealed evidence of numerous past rearrangements within the DNA sequence that encodes the CTD. Interestingly, the total number of CTD repeats was relatively static (24–26 repeats in all strains), suggesting a balancing act between repeat expansion and contraction. In an effort to explore the genetic plasticity within this region, we measured the rates of repeat expansion and contraction using novel reporters and a doxycycline-regulated expression system for RPB1. In efforts to determine the mechanisms leading to CTD repeat variability, we identified the presence of DNA secondary structures, specifically G-quadruplex-like DNA, within the CTD coding region. Furthermore, we demonstrated that mutating PIF1, a G-quadruplex-specific helicase, results in increased CTD repeat length polymorphisms. We also determined that RAD52 is necessary for CTD repeat expansion but not contraction, identifying a role for recombination in repeat expansion. Results from these DNA rearrangements may help explain the CTD copy number variation seen across eukaryotes, as well as support a model of CTD expansion and contraction to maintain CTD integrity and overall length. |
format | Online Article Text |
id | pubmed-4882425 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | American Society for Biochemistry and Molecular Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-48824252016-06-02 DNA Instability Maintains the Repeat Length of the Yeast RNA Polymerase II C-terminal Domain Morrill, Summer A. Exner, Alexandra E. Babokhov, Michael Reinfeld, Bradley I. Fuchs, Stephen M. J Biol Chem DNA and Chromosomes The C-terminal domain (CTD) of RNA polymerase II in eukaryotes is comprised of tandemly repeating units of a conserved seven-amino acid sequence. The number of repeats is, however, quite variable across different organisms. Furthermore, previous studies have identified evidence of rearrangements within the CTD coding region, suggesting that DNA instability may play a role in regulating or maintaining CTD repeat number. The work described here establishes a clear connection between DNA instability and CTD repeat number in Saccharomyces cerevisiae. First, analysis of 36 diverse S. cerevisiae isolates revealed evidence of numerous past rearrangements within the DNA sequence that encodes the CTD. Interestingly, the total number of CTD repeats was relatively static (24–26 repeats in all strains), suggesting a balancing act between repeat expansion and contraction. In an effort to explore the genetic plasticity within this region, we measured the rates of repeat expansion and contraction using novel reporters and a doxycycline-regulated expression system for RPB1. In efforts to determine the mechanisms leading to CTD repeat variability, we identified the presence of DNA secondary structures, specifically G-quadruplex-like DNA, within the CTD coding region. Furthermore, we demonstrated that mutating PIF1, a G-quadruplex-specific helicase, results in increased CTD repeat length polymorphisms. We also determined that RAD52 is necessary for CTD repeat expansion but not contraction, identifying a role for recombination in repeat expansion. Results from these DNA rearrangements may help explain the CTD copy number variation seen across eukaryotes, as well as support a model of CTD expansion and contraction to maintain CTD integrity and overall length. American Society for Biochemistry and Molecular Biology 2016-05-27 2016-03-29 /pmc/articles/PMC4882425/ /pubmed/27026700 http://dx.doi.org/10.1074/jbc.M115.696252 Text en © 2016 by The American Society for Biochemistry and Molecular Biology, Inc. Author's Choice—Final version free via Creative Commons CC-BY license (http://creativecommons.org/licenses/by/4.0) . |
spellingShingle | DNA and Chromosomes Morrill, Summer A. Exner, Alexandra E. Babokhov, Michael Reinfeld, Bradley I. Fuchs, Stephen M. DNA Instability Maintains the Repeat Length of the Yeast RNA Polymerase II C-terminal Domain |
title | DNA Instability Maintains the Repeat Length of the Yeast RNA Polymerase II C-terminal Domain |
title_full | DNA Instability Maintains the Repeat Length of the Yeast RNA Polymerase II C-terminal Domain |
title_fullStr | DNA Instability Maintains the Repeat Length of the Yeast RNA Polymerase II C-terminal Domain |
title_full_unstemmed | DNA Instability Maintains the Repeat Length of the Yeast RNA Polymerase II C-terminal Domain |
title_short | DNA Instability Maintains the Repeat Length of the Yeast RNA Polymerase II C-terminal Domain |
title_sort | dna instability maintains the repeat length of the yeast rna polymerase ii c-terminal domain |
topic | DNA and Chromosomes |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4882425/ https://www.ncbi.nlm.nih.gov/pubmed/27026700 http://dx.doi.org/10.1074/jbc.M115.696252 |
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