Phosphoenolpyruvate carboxykinase (Pck) catalyzes the first step of gluconeogenesis, and the gene which encodes this enzyme (pckA) is transcriptionally regulated. High pckA expression is observed in succinate-grown cells, while little expression is observed in glucose-grown cells. pckA regulatory mutants have previously been isolated (Osteras et al. 1997) and pckR, a gene encoding a Lacl-GaIR DNA-binding transcriptional regulator, has been implicated in the regulation of pckA transcription. Here we shew that pckR insertion mutations result in a dramatic decrease in pckA expression even in succinate-grown cells. We demonstrate that the previously identified rpk-9 mutation is tightly linked to pckR. The rpk-9 mutation results in constitutive pckA expression, and we show that plasmids carrying the pckR gene complement the rpk-9 mutation in glucose-grown cells. A putative Lacl-GaIR operator binding site has been identified in the pckA promoter, however no evidence of an interaction between this site and the pckR gene product could be found. / Thesis / Master of Science (MS)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/23544 |
| Date | 12 1900 |
| Creators | O'Brien, Shelley |
| Contributors | Finan, T. M., Biology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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