Skip to main content
bioRxiv
  • Home
  • About
  • Submit
  • ALERTS / RSS
Advanced Search
New Results

DnaA and SspA Regulation of the iraD gene of E. coli: an alternative DNA damage response independent of LexA/RecA

Thalia H. Sass, Alexander E. Ferrazzoli, View ORCID ProfileSusan T. Lovett
doi: https://doi.org/10.1101/2021.05.20.444958
Thalia H. Sass
Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, MA 02454-9110
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Alexander E. Ferrazzoli
Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, MA 02454-9110
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Susan T. Lovett
Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, MA 02454-9110
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Susan T. Lovett
  • For correspondence: lovett@brandeis.edu
  • Abstract
  • Full Text
  • Info/History
  • Metrics
  • Preview PDF
Loading

ABSTRACT

The transcription factor RpoS (σS) of Escherichia coli controls a large number of genes important for tolerance of a variety of stress conditions. IraD promotes the post-translation stability of RpoS by inhibition of RssB, an adaptor protein for ClpXP degradation. We have previously documented DNA damage induction of iraD expression, independent of the SOS response. Both iraD and rpoS are required for tolerance to DNA damaging treatments such as H2O2 and the replication inhibitor azidothymidine in the log phase of growth. Using luciferase gene fusions to the 672 bp iraD upstream region, we show here that both promoters of iraD are induced by AZT. Genetic analysis suggests that both promoters are repressed by DnaA-ATP, partially dependent on a putative DnaA box at −81 bp, and regulated by RIDA (regulatory inactivation of DnaA), dependent on the DnaN processivity clamp. By electrophoretic mobility shift assays we show that purified DnaA protein binds to the iraD upstream region, so DnaA regulation of IraD is likely to be direct. DNA damage induction of iraD during log phase growth is abolished in the dnaA-T174P mutant, suggesting that DNA damage, in some way, relieves DnaA repression, possibly through the accumulation of replication clamps and enhanced RIDA. We demonstrate that the RNA-polymerase associated factor, SspA (stringent starvation protein A), induced by the accumulation of ppGpp, also affects IraD expression, with a positive effect on constitutive expression and a negative effect on AZT-induced expression, in a fashion independent of DnaA.

SIGNIFICANCE DNA damage can lead to cell death or genomic instability. Cells have evolved transcriptional responses that sense DNA damage and up-regulate tolerance and repair factors; the LexA/RecA-regulated SOS response in E. coli was the first example of such a system. This work describes an alternative DNA damage response, controlled by DnaA and the IraD post-translational regulator of RpoS. The cellular signals for this response, we propose, are empty replication processivity (β) clamps that accumulate at replication blocks. IraD expression is also regulated by stringent starvation protein, SspA, induced by nutrient deprivation. This SOS-independent DNA damage response integrates a signal of incomplete replication with starvation to modulate expression of genes that promote the completion of replication.

Competing Interest Statement

The authors have declared no competing interest.

Footnotes

  • ↵† deceased

Copyright 
The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC 4.0 International license.
Back to top
PreviousNext
Posted May 20, 2021.
Download PDF
Email

Thank you for your interest in spreading the word about bioRxiv.

NOTE: Your email address is requested solely to identify you as the sender of this article.

Enter multiple addresses on separate lines or separate them with commas.
DnaA and SspA Regulation of the iraD gene of E. coli: an alternative DNA damage response independent of LexA/RecA
(Your Name) has forwarded a page to you from bioRxiv
(Your Name) thought you would like to see this page from the bioRxiv website.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Share
DnaA and SspA Regulation of the iraD gene of E. coli: an alternative DNA damage response independent of LexA/RecA
Thalia H. Sass, Alexander E. Ferrazzoli, Susan T. Lovett
bioRxiv 2021.05.20.444958; doi: https://doi.org/10.1101/2021.05.20.444958
Reddit logo Twitter logo Facebook logo LinkedIn logo Mendeley logo
Citation Tools
DnaA and SspA Regulation of the iraD gene of E. coli: an alternative DNA damage response independent of LexA/RecA
Thalia H. Sass, Alexander E. Ferrazzoli, Susan T. Lovett
bioRxiv 2021.05.20.444958; doi: https://doi.org/10.1101/2021.05.20.444958

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Subject Area

  • Genetics
Subject Areas
All Articles
  • Animal Behavior and Cognition (4377)
  • Biochemistry (9568)
  • Bioengineering (7080)
  • Bioinformatics (24813)
  • Biophysics (12594)
  • Cancer Biology (9940)
  • Cell Biology (14310)
  • Clinical Trials (138)
  • Developmental Biology (7940)
  • Ecology (12090)
  • Epidemiology (2067)
  • Evolutionary Biology (15971)
  • Genetics (10911)
  • Genomics (14721)
  • Immunology (9856)
  • Microbiology (23611)
  • Molecular Biology (9468)
  • Neuroscience (50791)
  • Paleontology (369)
  • Pathology (1537)
  • Pharmacology and Toxicology (2677)
  • Physiology (4004)
  • Plant Biology (8651)
  • Scientific Communication and Education (1507)
  • Synthetic Biology (2388)
  • Systems Biology (6419)
  • Zoology (1345)