010 - Hupp 1994 Res Microbiol 145.99.pdf (original) (raw)

Gene transcription and chromosome replication in Escherichia coli

Journal of bacteriology, 1997

Transcript levels of several Escherichia coli genes involved in chromosome replication and cell division were measured in dnaC2(Ts) mutants synchronized for chromosome replication by temperature shifts. Levels of transcripts from four of the genes, dam, nrdA, mukB, and seqA, were reduced at a certain stage during chromosome replication. The magnitudes of the decreases were similar to those reported previously ftsQ and ftsZ (P. Zhou and C. E. Helmstetter, J. Bacteriol. 176:6100-6106, 1994) but considerably less than those seen with dnaA, gidA, and mioC (P. W. Theisen, J. E. Grimwade, A. C. Leonard, J. A. Bogan, and C. E. Helmstetter, Mol. Microbiol. 10:575-584, 1993). The decreases in transcripts appeared to correlate with the estimated time at which the genes replicated. This same conclusion was reached in studies with synchronous cultures obtained with the baby machine in those instances in which periodicities in transcript levels were clearly evident. The transcriptional levels fo...

Modulation of cell wall synthesis by DNA replication in Escherichia coli during initiation of cell growth

Journal of bacteriology, 1987

Resting cells of Escherichia coli are able to initiate growth and murein biosynthesis in the presence of beta-lactam antibiotics binding to penicillin-binding proteins (PBPs) 1a and 1b (E. J. de la Rosa, M. A. de Pedro, and D. Vázquez, Proc. Natl. Acad. Sci. USA 82:5632-5635, 1985). Under these conditions, cells elongate normally until they approach the first doubling in mass, the time at which cell lysis starts. Assuming that coupling between DNA replication and cell division both in cells starting growth and in growing cells is essentially similar, triggering of the lytic response in the beta-lactam-treated cells coincides with the termination of the first round of DNA replication. This coincidence suggests that both events are interrelated. We investigated this possibility by studying the initiation of growth in cultures of wild-type strains and in cell division mutants treated with beta-lactams inhibiting PBPs 1a and 1b and with the DNA replication inhibitor nalidixic acid. Addi...