Measurement of in vivo expression of the recA gene of Escherichia coli by using lacZ gene fusions

J M Weisemann, C Funk, G M Weinstock
1984 Journal of Bacteriology  
A recA-lacZ protein fusion was constructed in vivo by using bacteriophage Mu d11301(Ap lac). The fusion contained the promoter and first 47 codons of the recA mutant, as determined by DNA sequence analysis. The fusion was cloned and used to construct a recA-lacZ operon fusion at the same site within the recA gene. These fusions were introduced into the Escherichia coli chromosome at the attachment site either as complete or cryptic prophages. Synthesis of P-galactosidase from these fusions was
more » ... nducible by UV radiation. As the UV dose was increased, induction became slower and persisted for a longer period of time. At low doses of UV radiation, more 0-galactosidase was produced in a uvrA mutant than in a wild-type strain; however, at high doses, no induced synthesis of ,1-galactosidase occurred in a uvrA mutant. recA+ strains carrying either the protein or operon fusion on a multicopy plasmid showed reduced survival after UV irradiation. This UV sensitivity was not exhibited by strains containing a single copy of either fusion, however; hence, the fusions provide a reliable measure of recA expression.
doi:10.1128/jb.160.1.112-121.1984 fatcat:zbkaufnarzccrivfyctuhtv5b4