Coupling of DNA replication to growth rate in Escherichia coli: a possible role for guanosine tetraphosphate.
Two promoters for the Escherichia coli operon that contains the four genes dnaA, dnaN, recF, and gyrB were found to be growth rate regulated and under stringent control. Transcript abundance relative to total RNA increased with the growth rate. Changes in transcription from the dnaAp1 and dnaAp2 promoters that were induced by amino acid starvation and chloramphenicol and were relA dependent were correlated with the stringent response. The abundance of these transcripts per total RNA also decreased in spoT mutants as the severity of the mutation increased (guanosine 5'-diphosphate 3'-diphosphate [ppGpp] basal levels increased). Because expression of these promoters appears to be inhibited by ppGpp, it is proposed that one mechanism for coupling DNA replication to the growth rate of bacteria is through ppGpp synthesis at the ribosome.
Department of Biology, San Diego State University, California 92182.
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AE
Chiaramello
J W
JW
Zyskind
D004261:DNA Replication; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development; D005798:Genes, Bacterial; D006150:Guanine Nucleotides / Q000502:physiology*; D006159:Guanosine Tetraphosphate / Q000502:physiology*; D009876:Operon; D011401:Promoter Regions, Genetic; D012329:RNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D015183:Restriction Mapping; D014158:Transcription, Genetic
D006150:Guanine Nucleotides; D012329:RNA, Bacterial; D006159:Guanosine Tetraphosphate