Cell division genes ftsQAZ in Escherichia coli require distant cis-acting signals upstream of ddlB for full expression.
A transcriptional reporter fusion has been introduced into the chromosomal ftsZ locus in such a way that all transcription that normally reaches ftsZ can be monitored. The new Phi(ftsZ-lacZ ) fusion yields four times more beta-galactosidase activity than a ddlB-ftsQAZ-lacZ fusion on a lambda prophage vector. A strongly polar ddlB ::Omega insertion prevents contributions from signals upstream of the ftsQAZ promoters and decreases transcription of the chromosomal Phi(ftsZ-lacZ ) fusion by 66%, demonstrating that around two-thirds of total ftsZ transcription require cis-acting elements upstream of ddlB. We suggest that those elements are distant promoters, and thus that the cell division and cell wall synthesis genes in the dcw gene cluster are to a large extent co-transcribed. The ddlB ::Omega insertion is lethal unless additional copies of ftsQA are provided or a compensatory decrease in FtsZ synthesis is made. This shows that ddlB is a dispensable gene, and reinforces the critical role of the FtsA/FtsZ ratio in septation. Using the new reporter fusion, it is demonstrated that ftsZ expression is not autoregulated.
Flärdh
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Departamento de Biología Celular y del Desarrollo, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
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D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division / Q000235:genetics; D003598:Cytoskeletal Proteins; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; C065103:FtsA protein, Bacteria; C489310:FtsA protein, E coli; C068023:FtsQ protein, E coli; C071525:FtsZ protein, Bacteria; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D001616:beta-Galactosidase