Excess of Yra1 RNA-Binding Factor Causes Transcription-Dependent Genome Instability, Replication Impairment and Telomere Shortening

PLoS Genet. 2016 Apr 1;12(4):e1005966. doi: 10.1371/journal.pgen.1005966. eCollection 2016 Apr.

Abstract

Yra1 is an essential nuclear factor of the evolutionarily conserved family of hnRNP-like export factors that when overexpressed impairs mRNA export and cell growth. To investigate further the relevance of proper Yra1 stoichiometry in the cell, we overexpressed Yra1 by transforming yeast cells with YRA1 intron-less constructs and analyzed its effect on gene expression and genome integrity. We found that YRA1 overexpression induces DNA damage and leads to a transcription-associated hyperrecombination phenotype that is mediated by RNA:DNA hybrids. In addition, it confers a genome-wide replication retardation as seen by reduced BrdU incorporation and accumulation of the Rrm3 helicase. In addition, YRA1 overexpression causes a cell senescence-like phenotype and telomere shortening. ChIP-chip analysis shows that overexpressed Yra1 is loaded to transcribed chromatin along the genome and to Y' telomeric regions, where Rrm3 is also accumulated, suggesting an impairment of telomere replication. Our work not only demonstrates that a proper stoichiometry of the Yra1 mRNA binding and export factor is required to maintain genome integrity and telomere homeostasis, but suggests that the cellular imbalance between transcribed RNA and specific RNA-binding factors may become a major cause of genome instability mediated by co-transcriptional replication impairment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • DNA Replication*
  • Genes, Fungal
  • Genomic Instability*
  • Nuclear Proteins / physiology*
  • Nucleic Acid Hybridization
  • RNA-Binding Proteins / physiology*
  • Recombination, Genetic
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins / physiology*
  • Telomere Shortening*
  • Transcription, Genetic*

Substances

  • Nuclear Proteins
  • RNA-Binding Proteins
  • Saccharomyces cerevisiae Proteins
  • YRA1 protein, S cerevisiae

Grant support

This work was funded by grants from the Spanish Ministry of Science and Innovation (BFU2010-16372, BFU2013-42918), the Junta de Andalucía (BIO102, CVI4567 and BIO1238) and the European Union (FEDER). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.