University of Nevada, Las Vegas; Center for Academic Enrichment and Outreach
It is widely known and accepted that the cause of many mutations in cells are generated during the replication process of actively dividing cells, however more recent research has shown that mutations also arise in non growing conditions, a phenomenon known as stationary phase mutagenesis. Much of what is known come from studies in eukaryotic and bacterial models. It has been proposed that in non-growing cells, the process of transcription plays an important role in mutagenesis. We test the hypothesis that DNA secondary structures, formed during transcription, promote mutagenesis. The transcription-generated structures are speculated to be prone to by blocking the RNA polymerase which has potential to trigger a gratuitous response from transcription coupled repair proteins like mfd. Genes up-regulated in response to stress with secondary structures can accumulate mutations due to this gratuitous repair. To test this hypothesis, I am using two Bacillus subtilis genes, argF and thiF, predicted by in silico, to form secondary structures. By altering the base sequence of these genes, the stability of their stem-loop structures are affected, thereby allowing us to test whether transcription of the altered sequence influences the accumulation of mutations in argF and thiF by impeding the RNA polymerase. Our assay for detecting mutations is based on phenotypic reversion back to prototrophy in cells under conditions of starvation. Ultimately, these experiments will increase our understanding of how mutations occur in cells of all domains of life.
DNA repair; Genetic transcription; Mutagenesis; RNA polymerases
Genetics | Genetics and Genomics
Martin, H. A.,
DNA secondary structures and their contribution to mutagenesis in B. subtilis stationary phase cells..
Available at: http://digitalscholarship.unlv.edu/mcnair_posters/17