When the E. coli chromosome is damaged or its synthesis inhibited, a variety of new cellular functions are expressed: these include phage induction, induction of recA protein, new DNA repair ability and mutagenesis. Our objective is to understand how these functions become expressed at the molecular level. The product of the recA gene, which regulates the expression of these inducible functions is a highly specific ATP and polynucleotide dependent protease. We have shown that in crude cellular extracts it cleaves the product of another E. coli gene, lexA, which also regulates the induction mechanism. We wish to study this cleavage reaction and compare it to the cleavage of phage lambda repressor by the recA protease. To determine the intracellular significance of the cleavage reaction, we will study cleavage of mutant lexA proteins or phage repressors produced by a set of host or phage mutants which show an altered response to induction. Mutant recA proteins, including those from some new types of mutants which we propose to isolate in this study, will also be tested. Finally, we will look for evidence of cleavage of the products of other genes and other proteins implicated in expression of SOS functions. The recA protein made in induced cells will be analyzed in a search for one or more biochemical alterations following induction. An in vitro system for measuring fidelity of DNA replication will be established and the influence of recA protein on this system will be studied.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM024496-08
Application #
3272355
Study Section
(MG)
Project Start
1978-01-01
Project End
1985-12-31
Budget Start
1985-01-01
Budget End
1985-12-31
Support Year
8
Fiscal Year
1985
Total Cost
Indirect Cost
Name
University of Arizona
Department
Type
Schools of Arts and Sciences
DUNS #
City
Tucson
State
AZ
Country
United States
Zip Code
85722
Lewis, L K; Harlow, G R; Gregg-Jolly, L A et al. (1994) Identification of high affinity binding sites for LexA which define new DNA damage-inducible genes in Escherichia coli. J Mol Biol 241:507-23
Peterson, K R; Mount, D W (1993) Analysis of the genetic requirements for viability of Escherichia coli K-12 DNA adenine methylase (dam) mutants. J Bacteriol 175:7505-8
Ennis, D G; Little, J W; Mount, D W (1993) Novel mechanism for UV sensitivity and apparent UV nonmutability of recA432 mutants: persistent LexA cleavage following SOS induction. J Bacteriol 175:7373-82
Lewis, L K; Jenkins, M E; Mount, D W (1992) Isolation of DNA damage-inducible promoters in Escherichia coli: regulation of polB (dinA), dinG, and dinH by LexA repressor. J Bacteriol 174:3377-85
Mustard, J A; Thliveris, A T; Mount, D W (1992) Sequence of the Salmonella typhimurium LT2 lexA gene and its regulatory region. Nucleic Acids Res 20:1813
Thliveris, A T; Mount, D W (1992) Genetic identification of the DNA binding domain of Escherichia coli LexA protein. Proc Natl Acad Sci U S A 89:4500-4
Lewis, L K; Mount, D W (1992) Interaction of LexA repressor with the asymmetric dinG operator and complete nucleotide sequence of the gene. J Bacteriol 174:5110-6
Dubnick, M; Thliveris, A T; Mount, D W (1991) Mixed oligo designer (MOD), a computer program to aid planning of automated, mixed oligodeoxyribonucleotide synthesis for mutagenesis experiments. Gene 105:1-7
Thliveris, A T; Little, J W; Mount, D W (1991) Repression of the E coli recA gene requires at least two LexA protein monomers. Biochimie 73:449-56
Dubnick, M; Mount, D W (1990) SPLICE, a computer program for automated extraction of information from GenBank sequence entries. Comput Appl Biosci 6:343-6

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