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Title: Antisense regulation of cell division in Escherichia coli
Author: Geddes, Auste
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2002
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BACKGROUND: FtsZ is an essential cell division protein in bacteria. It is involved in the initiation, timing, and frequency of cell divisions. Consequently it is subject to strict regulation, including transcriptional and post-transcriptional control and protein inhibition. Regulation of ftsZ expression by an antisense RNA has also been proposed. Dewar and Donachie suggested that there is a gene stfZ encoded by the antisense strand of DNA at the ftsA-ftsA gene junction in the mra gene cluster of the Escherichia coli chromosome. Multiple copies of the DNA fragment containing the stfZ gene block cell division. Since an RNA transcribed from stfZ would be complementary to the ribosomal binding site of ftsZ, it has been proposed that the product of stfZ is an antisense RNA that controls translation of ftsZ. RESULTS: To see if there are other antisense genes in the mra gene cluster of the E. coli chromosome, we looked for antisense promoters and terminators in the region. While no promoters have been identified, all the DNA fragments that have been tested had strong termination activity. Northern blotting, RT-PCR, and primer extension experiments confirm that there is an RNA produced from the antisense strand of DNA at the ftsA-ftsZ gene junction of E. coli cells. RT-PCR experiments indicate that the StfZ RNA is at least 423 nt long. Overexpression of an artificial RNA containing a part of the StfZ sequence lowers FtsZ concentration in cells, prevents FtsZ ring formation, and inhibits cell division. Experiments with fusion constructs show that the overexpressed RNA acts on the ribosomal binding site (RBS) of ftsZ. Other experiments using the fusion constructs indicate that the expression from the RBS of ftsZ is strongly dependent on the growth phase of cells. CONCLUSIONS: The antisense RNA StfZ is produced in E. coli cells. It is very likely that StfZ controls translation of ftsZ, and that it does this by binding to the RBS of the ftsZ mRNA.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available