Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2003-1-17
pubmed:abstractText
UV irradiation of E. coli produces photoproducts in the DNA genome. In consequence, some bacteria lose viability (colony-forming ability) or remain viable as mutant cells. However, the end-points of viability inactivation (lethality) or mutation are determined by cellular processes that act on the UV-damaged DNA. We have investigated the in vivo time course for processes that deal with cyclobutane pyrimidine dimers (CPD) which can be specifically removed by photoreactivation (PR). At different times during post-UV incubation, samples were challenged with PR and assayed for viability or mutation. We used excision-defective E. coli B/r cells and worked under yellow light to avoid background PR. During post-UV incubation (0-100min) in fully supplemented defined medium, inactivation and mutation were initially significantly reversed by PR but the extent of this reversal decreased during continued incubation defining "fixation" of lethality or mutation, respectively. In contrast, if protein synthesis was restricted during the post-UV incubation, no fixation developed. When chloramphenicol was added to inhibit protein synthesis after 30min of supplemented post-UV incubation, at a time sufficient for expression of UV-induced protein(s), fixation of lethality or mutation was still annulled (no change in the effectiveness of PR developed). Lethality fixation did progress when protein synthesis was restricted and the cells were incubated in the presence of puromycin or were either clpP or clpX defective. We discuss these and related results to suggest (1) on-going protein synthesis is required in the fixation process for lethality and mutation to sustain an effective level of a hypothetical protein sensitive to ClpXP proteolysis and (2) this protein plays a critical role in the process leading to exchange between Pol III activity and alternative polymerase activities required as each cell deals with damage in template DNA.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1568-7864
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
1
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
821-31
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:12531029-Adenosine Triphosphatases, pubmed-meshheading:12531029-Cell Survival, pubmed-meshheading:12531029-Chloramphenicol, pubmed-meshheading:12531029-DNA, Bacterial, pubmed-meshheading:12531029-DNA Damage, pubmed-meshheading:12531029-DNA Polymerase III, pubmed-meshheading:12531029-DNA Repair, pubmed-meshheading:12531029-DNA Replication, pubmed-meshheading:12531029-Endopeptidase Clp, pubmed-meshheading:12531029-Escherichia coli, pubmed-meshheading:12531029-Escherichia coli Proteins, pubmed-meshheading:12531029-Mutagenesis, pubmed-meshheading:12531029-Mutation, pubmed-meshheading:12531029-Protein Synthesis Inhibitors, pubmed-meshheading:12531029-Puromycin, pubmed-meshheading:12531029-Pyrimidine Dimers, pubmed-meshheading:12531029-Serine Endopeptidases, pubmed-meshheading:12531029-Suppression, Genetic, pubmed-meshheading:12531029-Ultraviolet Rays
pubmed:year
2002
pubmed:articleTitle
DNA damage-processing in E. coli: on-going protein synthesis is required for fixation of UV-induced lethality and mutation.
pubmed:affiliation
Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.