scholarly journals Role of DNA Replication and Repair in Thymineless Death in Escherichia coli

2006 ◽  
Vol 188 (14) ◽  
pp. 5286-5288 ◽  
Author(s):  
Pamela A. Morganroth ◽  
Philip C. Hanawalt
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Excision Repair ◽  
Thymine Starvation ◽  
Nucleotide Excision ◽  
Dna Replication And Repair ◽  
Thymineless Death ◽  
Dna Repair Mutants ◽  
Rule Out

ABSTRACT Inhibition of DNA replication with hydroxyurea during thymine starvation of Escherichia coli shows that active DNA synthesis is not required for thymineless death (TLD). Hydroxyurea experiments and thymine starvation of lexA3 and uvrA DNA repair mutants rule out unbalanced growth, the SOS response, and nucleotide excision repair as explanations for TLD.

The role of nucleotide excision repair of Escherichia coli in repair of spontaneous and gamma-radiation-induced DNA damage in the lacZα gene

2000 ◽  
Vol 460 (2) ◽  
pp. 117-125 ◽  
Author(s):  
Gitta K Kuipers ◽  
Ben J Slotman ◽  
Hester A Poldervaart ◽  
Ingrid M.J van Vilsteren ◽  
Carola A Reitsma-Wijker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Damage ◽  
Gamma Radiation ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Nucleotide Excision ◽  
Radiation Induced

scholarly journals lon Incompatibility Associated with Mutations Causing SOS Induction: Null uvrD Alleles Induce an SOS Response in Escherichia coli

2000 ◽  
Vol 182 (11) ◽  
pp. 3151-3157 ◽  
Author(s):  
L. SaiSree ◽  
Manjula Reddy ◽  
J. Gowrishankar
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Mismatch Repair ◽  
Replication Fork ◽  
Excision Repair ◽  
Dna Helicase ◽  
Lon Protease ◽  
Sos Induction ◽  
Nucleotide Excision ◽  
Lagging Strand

ABSTRACT The uvrD gene in Escherichia coli encodes a 720-amino-acid 3′-5′ DNA helicase which, although nonessential for viability, is required for methyl-directed mismatch repair and nucleotide excision repair and furthermore is believed to participate in recombination and DNA replication. We have shown in this study that null mutations in uvrD are incompatible withlon, the incompatibility being a consequence of the chronic induction of SOS in uvrD strains and the resultant accumulation of the cell septation inhibitor SulA (which is a normal target for degradation by Lon protease). uvrD-lonincompatibility was suppressed by sulA,lexA3(Ind−), or recA (Def) mutations. Other mutations, such as priA, dam,polA, and dnaQ (mutD) mutations, which lead to persistent SOS induction, were also lonincompatible. SOS induction was not observed in uvrC andmutH (or mutS) mutants defective, respectively, in excision repair and mismatch repair. Nor wasuvrD-mediated SOS induction abolished by mutations in genes that affect mismatch repair (mutH), excision repair (uvrC), or recombination (recB andrecF). These data suggest that SOS induction inuvrD mutants is not a consequence of defects in these three pathways. We propose that the UvrD helicase participates in DNA replication to unwind secondary structures on the lagging strand immediately behind the progressing replication fork, and that it is the absence of this function which contributes to SOS induction inuvrD strains.

scholarly journals Role of the Escherichia coli Nucleotide Excision Repair Proteins in DNA Replication

2000 ◽  
Vol 182 (20) ◽  
pp. 5706-5714 ◽  
Author(s):  
Geri F. Moolenaar ◽  
Celine Moorman ◽  
Nora Goosen
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Inhibitory Effect ◽  
Binding Domain ◽  
Nucleotide Excision ◽  
Polymerase I

ABSTRACT DNA polymerase I (PolI) functions both in nucleotide excision repair (NER) and in the processing of Okazaki fragments that are generated on the lagging strand during DNA replication.Escherichia coli cells completely lacking the PolI enzyme are viable as long as they are grown on minimal medium. Here we show that viability is fully dependent on the presence of functional UvrA, UvrB, and UvrD (helicase II) proteins but does not require UvrC. In contrast, ΔpolA cells grow even better when theuvrC gene has been deleted. Apparently UvrA, UvrB, and UvrD are needed in a replication backup system that replaces the PolI function, and UvrC interferes with this alternative replication pathway. With specific mutants of UvrC we could show that the inhibitory effect of this protein is related to its catalytic activity that on damaged DNA is responsible for the 3′ incision reaction. Specific mutants of UvrA and UvrB were also studied for their capacity to support the PolI-independent replication. Deletion of the UvrC-binding domain of UvrB resulted in a phenotype similar to that caused by deletion of the uvrC gene, showing that the inhibitory incision activity of UvrC is mediated via binding to UvrB. A mutation in the N-terminal zinc finger domain of UvrA does not affect NER in vivo or in vitro. The same mutation, however, does give inviability in combination with the ΔpolA mutation. Apparently the N-terminal zinc-binding domain of UvrA has specifically evolved for a function outside DNA repair. A model for the function of the UvrA, UvrB, and UvrD proteins in the alternative replication pathway is discussed.

scholarly journals The role of nucleotide excision repair in protecting embryonic stem cells from genotoxic effects of UV-induced DNA damage

1999 ◽  
Vol 27 (16) ◽  
pp. 3276-3282 ◽  
Author(s):  
P. P. H. Van Sloun ◽  
J. G. Jansen ◽  
G. Weeda ◽  
L. H. F. Mullenders ◽  
A. A. van Zeeland ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dna Damage ◽  
Embryonic Stem Cells ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Embryonic Stem ◽  
Genotoxic Effects ◽  
Nucleotide Excision
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