Relationship between cellular RecA protein concentration and untargeted mutagenesis in Escherichia coli

Shukti Chakravarti, Beverly Hamilton, Raquel Sussman

Research output: Contribution to journalArticle

Abstract

We measured the production of untargeted mutations in the cI and cII genes of untreated λ phage undergoing a lytic cycle in UV-irradiated bacterial hosts. As previously shown, treatment with 4 μg/ml of rifampicin during post-irradiation incubation inhibited amplification of the RecA protein in these cells. In addition, we observed a decreased mutation rate compared to the untreated, irradiated bacteria. Treatment with 4 μg/ml or 8 μg/ml rifampicin did not prevent the UV induction of the umuDC operon, as judged by assay of β-galactosidase activity in a umuC-lacZ fusion strain. In contrast, the UV-induction of β-galactosidase in the sulA-lacZ fusion strain was decreased by 4 μg/ml rifampicin. The inhibition of untargeted mutagenesis by this drug treatment was also observed in a strain constitutive for SOS functions (lexA (Def)) as well as ina RecA-overproducing plasmid strain, that blocks induction of heat-shock proteins, factor(s) in wild-type recA+ cells. An htpR165-carrying strain, that blocks induction of heat-shock proteins, exhibited normal UV-promoted mutagenesis. A correlation was observed between the cellular concentration of RecA protein, increased spontaneously by a temperature shift in a lexA(Ts) strain, and the extent of UV-promoted untargeted mutagenesis. These results suggest a mechanistic role of RecA protein in this process.

Original languageEnglish (US)
Pages (from-to)179-193
Number of pages15
JournalMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
Volume160
Issue number3
DOIs
StatePublished - 1986
Externally publishedYes

Fingerprint

Rec A Recombinases
Rifampin
Galactosidases
Mutagenesis
Escherichia coli
Heat-Shock Proteins
Mutation Rate
Operon
Bacteriophages
Plasmids
Bacteria
Mutation
Temperature
Pharmaceutical Preparations
Genes

ASJC Scopus subject areas

  • Molecular Biology
  • Health, Toxicology and Mutagenesis
  • Medicine(all)

Cite this

Relationship between cellular RecA protein concentration and untargeted mutagenesis in Escherichia coli. / Chakravarti, Shukti; Hamilton, Beverly; Sussman, Raquel.

In: Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, Vol. 160, No. 3, 1986, p. 179-193.

Research output: Contribution to journalArticle

@article{a68ee56430d64c169dabbc23f326e843,
title = "Relationship between cellular RecA protein concentration and untargeted mutagenesis in Escherichia coli",
abstract = "We measured the production of untargeted mutations in the cI and cII genes of untreated λ phage undergoing a lytic cycle in UV-irradiated bacterial hosts. As previously shown, treatment with 4 μg/ml of rifampicin during post-irradiation incubation inhibited amplification of the RecA protein in these cells. In addition, we observed a decreased mutation rate compared to the untreated, irradiated bacteria. Treatment with 4 μg/ml or 8 μg/ml rifampicin did not prevent the UV induction of the umuDC operon, as judged by assay of β-galactosidase activity in a umuC-lacZ fusion strain. In contrast, the UV-induction of β-galactosidase in the sulA-lacZ fusion strain was decreased by 4 μg/ml rifampicin. The inhibition of untargeted mutagenesis by this drug treatment was also observed in a strain constitutive for SOS functions (lexA (Def)) as well as ina RecA-overproducing plasmid strain, that blocks induction of heat-shock proteins, factor(s) in wild-type recA+ cells. An htpR165-carrying strain, that blocks induction of heat-shock proteins, exhibited normal UV-promoted mutagenesis. A correlation was observed between the cellular concentration of RecA protein, increased spontaneously by a temperature shift in a lexA(Ts) strain, and the extent of UV-promoted untargeted mutagenesis. These results suggest a mechanistic role of RecA protein in this process.",
author = "Shukti Chakravarti and Beverly Hamilton and Raquel Sussman",
year = "1986",
doi = "10.1016/0027-5107(86)90127-2",
language = "English (US)",
volume = "160",
pages = "179--193",
journal = "Mutation Research",
issn = "0027-5107",
publisher = "Elsevier",
number = "3",

}

TY - JOUR

T1 - Relationship between cellular RecA protein concentration and untargeted mutagenesis in Escherichia coli

AU - Chakravarti, Shukti

AU - Hamilton, Beverly

AU - Sussman, Raquel

PY - 1986

Y1 - 1986

N2 - We measured the production of untargeted mutations in the cI and cII genes of untreated λ phage undergoing a lytic cycle in UV-irradiated bacterial hosts. As previously shown, treatment with 4 μg/ml of rifampicin during post-irradiation incubation inhibited amplification of the RecA protein in these cells. In addition, we observed a decreased mutation rate compared to the untreated, irradiated bacteria. Treatment with 4 μg/ml or 8 μg/ml rifampicin did not prevent the UV induction of the umuDC operon, as judged by assay of β-galactosidase activity in a umuC-lacZ fusion strain. In contrast, the UV-induction of β-galactosidase in the sulA-lacZ fusion strain was decreased by 4 μg/ml rifampicin. The inhibition of untargeted mutagenesis by this drug treatment was also observed in a strain constitutive for SOS functions (lexA (Def)) as well as ina RecA-overproducing plasmid strain, that blocks induction of heat-shock proteins, factor(s) in wild-type recA+ cells. An htpR165-carrying strain, that blocks induction of heat-shock proteins, exhibited normal UV-promoted mutagenesis. A correlation was observed between the cellular concentration of RecA protein, increased spontaneously by a temperature shift in a lexA(Ts) strain, and the extent of UV-promoted untargeted mutagenesis. These results suggest a mechanistic role of RecA protein in this process.

AB - We measured the production of untargeted mutations in the cI and cII genes of untreated λ phage undergoing a lytic cycle in UV-irradiated bacterial hosts. As previously shown, treatment with 4 μg/ml of rifampicin during post-irradiation incubation inhibited amplification of the RecA protein in these cells. In addition, we observed a decreased mutation rate compared to the untreated, irradiated bacteria. Treatment with 4 μg/ml or 8 μg/ml rifampicin did not prevent the UV induction of the umuDC operon, as judged by assay of β-galactosidase activity in a umuC-lacZ fusion strain. In contrast, the UV-induction of β-galactosidase in the sulA-lacZ fusion strain was decreased by 4 μg/ml rifampicin. The inhibition of untargeted mutagenesis by this drug treatment was also observed in a strain constitutive for SOS functions (lexA (Def)) as well as ina RecA-overproducing plasmid strain, that blocks induction of heat-shock proteins, factor(s) in wild-type recA+ cells. An htpR165-carrying strain, that blocks induction of heat-shock proteins, exhibited normal UV-promoted mutagenesis. A correlation was observed between the cellular concentration of RecA protein, increased spontaneously by a temperature shift in a lexA(Ts) strain, and the extent of UV-promoted untargeted mutagenesis. These results suggest a mechanistic role of RecA protein in this process.

UR - http://www.scopus.com/inward/record.url?scp=0022517238&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0022517238&partnerID=8YFLogxK

U2 - 10.1016/0027-5107(86)90127-2

DO - 10.1016/0027-5107(86)90127-2

M3 - Article

C2 - 2938000

AN - SCOPUS:0022517238

VL - 160

SP - 179

EP - 193

JO - Mutation Research

JF - Mutation Research

SN - 0027-5107

IS - 3

ER -