Affiliation:
1. Department of Biological Sciences, University at Buffalo, Buffalo, New York 14260
Abstract
ABSTRACT
The affinities of the bacteriophage 434 repressor for its various binding sites depend on the type and/or concentration of monovalent cations. The ability of bacteriophage 434 repressor to govern the lysis-lysogeny decision depends on the DNA binding activities of the phage's
c
I repressor protein. We wished to determine whether changes in the intracellular ionic environment influence the lysis-lysogeny decision of the bacteriophage λ
imm434
. Our findings show that the ionic composition within bacterial cells varies with the cation concentration in the growth media. When λ
imm434
lysogens were grown to mid-log or stationary phase and subsequently incubated in media with increasing monovalent salt concentrations, we observed a salt concentration-dependent increase in the frequency of bacteriophage spontaneous induction. We also found that the frequency of spontaneous induction varied with the type of monovalent cation in the medium. The salt-dependent increase in phage production was unaffected by a
recA
mutation. These findings indicate that the salt-dependent increase in phage production is not caused by activation of the SOS pathway. Instead, our evidence suggests that salt stress induces this lysogenic bacteriophage by interfering with 434 repressor-DNA interactions. We speculate that the salt-dependent increase in spontaneous induction is due to a direct effect on the repressor's affinity for DNA. Regardless of the precise mechanism, our findings demonstrate that salt stress can regulate the phage lysis-lysogeny switch.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference56 articles.
1. Arber, W., L. Enquist, B. Hohn, N. E. Murray, and K. Murray. 1983. In R. W. Hendrix, J. W. Roberts, F. W. Stahl, and R. A. Weisberg (ed.), Lambda II, p. 433-466. Cold Spring Harbor Laboratory, Cold Spring Harbor, NY.
2. Bell, A. C., and G. B. Koudelka. 1993. Operator sequence context influences amino acid-base-pair interactions in 434 repressor-operator complexes. J. Mol. Biol. 234 : 542-553.
3. Bell, A. C., and G. B. Koudelka. 1995. How 434 repressor discriminates between OR1 and OR3. The influence of contacted and noncontacted base pairs. J. Biol. Chem. 270 : 1205-1212.
4. Bergqvist, S., R. O'Brien, and J. E. Ladbury. 2001. Site-specific cation binding mediates TATA binding protein-DNA interaction from a hyperthermophilic archaeon. Biochemistry 40 : 2419-2425.
5. Bergqvist, S., M. A. Williams, R. O'Brien, and J. E. Ladbury. 2003. Halophilic adaptation of protein-DNA interactions. Biochem. Soc. Trans. 31 : 677-680.
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