
Full text loading...
Bacteriophage λ is unable to lysogenize Escherichia coli hosts harbouring the rpoA341 mutation due to a drastic reduction in transcription from CII-activated lysogenic promoters (p E, p 1 and p aQ). In addition, the level of early transcripts involved in the lytic pathway of λ development is also decreased in this genetic background due to impaired N-dependent antitermination. Here, it is demonstrated that despite the reduced level of early lytic p L- and p R-derived transcripts, lytic growth of bacteriophage λ is not affected in rich media. The level of the late lytic, p R-derived transcripts also remains unaffected by the rpoA341 mutation under these conditions. However, it was found that whilst there is no significant difference in the phage burst size in rpoA + and rpoA341 hosts growing in rich media, phage λ is not able to produce progeny in the rpoA341 mutant growing in minimal medium, in contrast to otherwise isogenic rpoA + bacteria. Provision of an excess of the phage replication proteins O and P in trans or overproduction of the antitermination protein N restore the ability of phage λ to produce progeny in the rpoA341 mutant under the latter conditions. These results suggest that in rich media phage λ produces some early proteins in excess of that needed for its effective propagation and indicate that replication proteins may be limiting factors for phage lytic growth in poor media.
Article metrics loading...
Full text loading...
References
Data & Media loading...