198 -- The Impact of DNA Methyltransferase on Bacterial Growth in E. Coli

The Dcm protein (DNA cytosine methyltransferase) catalyzes the process of DNA methylation, a process that has a large role in the regulation of gene expression in cells. The Dcm protein methylates at the second C at the 5’CCWGG3’ site. The specific consequences of this methylation are not known. We have been studying DNA methylation in E. coli by using two different measures of growth. The first experiment was a growth curve using absorption spectroscopy of wild-type E. coli and E. coli with a Dcm knockout gene at a temperature stressor of 42°C. We tracked the growth over eight hours, after first growing cultures at 37°C since the bacteria had no difference in growth at that temperature. The second experiment used the same methods, but instead of the wild-type bacteria, a Dcm knockout strain with a Dcm plasmid added back in via genetic complementation was used. We also plated overnight cultures of the wild-type E. coli and Dcm knockout strains to utilize another mechanism to measure growth. It was found that the wild-type E. coli strain grew at the fastest rate of the four strains. This raises some questions regarding the significance of the Dcm gene, as the bacteria grows fastest when the Dcm gene has been present in the protein from start to finish. If the Dcm gene can withstand the high temperature stressors, we may be able to explore how the protein in bacteria may react to other stressors, and dissect possible medical and pharmaceutical implications