The role and function of hepatotoxins microcystin and nodularin produced by M.aeruginosa PCC 7806 and N. spumigena NSORlO respectively have yet to be elucidated. The mode of transcriptional regulation of these toxins, incorporating DNA binding proteins, was investigated, as an attempt to further understand the key control mechanisms acting on the toxins. The DNA binding proteins that control nitrogen and iron responsive transcription, NtcA and Fur, were identified from M. aeruginosa PCC7806 and N. spumigena NSOR10. Cloning and over-expression in E. coli was followed by mobility shift assays to determine binding characteristics of NtcA and Fur to the promoters, mcyA/D and ndaA/C, those regions that control the toxin encoding gene clusters in M. aeruginosa PCC 7806 and N. spumigena NSOR10, respectively. The results from these studies suggested a role for iron and nitrogen in the transcriptional control of microcystin and nodularin. biosynthesis. As NtcA and Fur classically act to regulate nitrogen and iron dependent genes, a link may be made to the putative function and control of microcystin and nodularin. By identifying the transcription factors NtcA and Fur in these genera, a greater understanding of the link between nutrient levels in the environment and hepatotoxin production in cyanobacteria may be possible.
| Identifer | oai:union.ndltd.org:ADTP/258610 |
| Date | January 2008 |
| Creators | Root, Hannah Patricia, Biotechnology & Biomolecular Sciences, Faculty of Science, UNSW |
| Publisher | Publisher:University of New South Wales. Biotechnology & Biomolecular Sciences |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | http://unsworks.unsw.edu.au/copyright, http://unsworks.unsw.edu.au/copyright |
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