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 <i>ftsZ</i> expression by an antisense RNA has also been proposed. Dewar and Donachie suggested that there is a gene <i>stfZ</i> encoded by the antisense strand of DNA at the <i>ftsA-ftsA </i>gene junction in the <i>mra </i>gene cluster of the <i>Escherichia coli</i> chromosome. Multiple copies of the DNA fragment containing the <i>stfZ</i> gene block cell division. Since an RNA transcribed from <i>stfZ</i> would be complementary to the ribosomal binding site of <i>ftsZ</i>, it has been proposed that the product of <i>stfZ</i> is an antisense RNA that controls translation of <i>ftsZ</i>. RESULTS: To see if there are other antisense genes in the <i>mra</i> gene cluster of the <i>E. coli</i> 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 <i>ftsA-ftsZ</i> gene junction of <i>E. coli</i> 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 <i>ftsZ</i>. Other experiments using the fusion constructs indicate that the expression from the RBS of <i>ftsZ</i> is strongly dependent on the growth phase of cells. CONCLUSIONS: The antisense RNA StfZ is produced in <i>E. coli</i> cells. It is very likely that StfZ controls translation of <i>ftsZ</i>, and that it does this by binding to the RBS of the <i>ftsZ</i> mRNA.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:651374 |
| Date | January 2002 |
| Creators | Geddes, Auste |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/13882 |
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