This proposal describes approaches designed to characterize a putative link between translation and DNA replication. The investigator has obtained preliminary evidence that there is an inducible mutagenic response called translational stress-induced mutagenesis (TSM). He found that the mutA and mutC mutator genes have a base substitution in the anticodons of the glyV or glyW tRNA genes that allow the mutant tRNAs to decode aspartate codons as glycine. The mutator phenotype is constitutive and the investigator argues that the phenotype is not due to rare glycine substitutions in the epsilon proofreading subunit of DNA polymerase III. In addition, the phenotype is recA-dependent but does not require functional umuD/C genes. The working hypothesis is that the pathway is recA-dependent but SOS-independent and is a response to translational stress rather than a result of mistranslation itself. The epsilon protein could be involved but the critical events in mutA cells are upstream of the epsilon subunit. Dr. Humayun proposes to carry-out three sets of experiments to further characterize the TSM response. The first set of experiments will test the hypothesis that translational stress rather than a specific amino acid substitution in a particular protein(s) induces TSM and will define the range of translational stress conditions that induce TSM. The second set of experiments will determine if translational stress will alter DNA replication fidelity by comparing DNA replication activities in induced and uninduced cells in an in vitro system. The third project will characterize how the TSM response differs from the umuD/C-dependent SOS pathway.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM058253-03
Application #
6180863
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Program Officer
Rhoades, Marcus M
Project Start
1998-08-01
Project End
2002-07-31
Budget Start
2000-08-01
Budget End
2001-07-31
Support Year
3
Fiscal Year
2000
Total Cost
$210,055
Indirect Cost
Name
University of Medicine & Dentistry of NJ
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
605799469
City
Newark
State
NJ
Country
United States
Zip Code
07107
Humayun, M Zafri; Ayyappan, Vasudevan (2013) Potential roles for DNA replication and repair functions in cell killing by streptomycin. Mutat Res 749:87-91
Gautam, Satyendra; Kalidindi, Raju; Humayun, M Zafri (2012) SOS induction and mutagenesis by dnaQ missense alleles in wild type cells. Mutat Res 735:46-50
Al Mamun, Abu Amar M; Humayun, M Zafri (2009) Spontaneous mutagenesis is elevated in protease-defective cells. Mol Microbiol 71:629-39
Al Mamun, Abu Amar M (2007) Elevated expression of DNA polymerase II increases spontaneous mutagenesis in Escherichia coli. Mutat Res 625:29-39
Al, Mamun Abu Amar M; Gautam, Satyendra; Humayun, M Zafri (2006) Hypermutagenesis in mutA cells is mediated by mistranslational corruption of polymerase, and is accompanied by replication fork collapse. Mol Microbiol 62:1752-63
Wang, Ge; Alamuri, Praveen; Humayun, M Zafri et al. (2005) The Helicobacter pylori MutS protein confers protection from oxidative DNA damage. Mol Microbiol 58:166-76
Balashov, Sergey; Humayun, M Zafri (2004) Specificity of spontaneous mutations induced in mutA mutator cells. Mutat Res 548:9-18
Balashov, Sergey; Humayun, M Zafri (2003) Escherichia coli cells bearing a ribosomal ambiguity mutation in rpsD have a mutator phenotype that correlates with increased mistranslation. J Bacteriol 185:5015-8
Al Mamun, Abu Amar M; Marians, Kenneth J; Humayun, M Zafri (2002) DNA polymerase III from Escherichia coli cells expressing mutA mistranslator tRNA is error-prone. J Biol Chem 277:46319-27
Dorazi, Robert; Lingutla, Josephine J; Humayun, M Zafri (2002) Expression of mutant alanine tRNAs increases spontaneous mutagenesis in Escherichia coli. Mol Microbiol 44:131-41

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