The role of alkylguanine-DNA alkyltransferase in the repair of DNA alkylating damage in Chlamydomonas reinhardtii

Andrea Sevcovicova, Alena Hercegova, Eliska Galova, and Daniel Vlcek

Department of Genetics, Faculty of Natural Sciences, Comenius University, Mlynska dolina, 842 15 Bratislava, Slovakia

The enzyme alkylguanine-DNA alkyltransferase catalyzes the transfer of the methyl group from methylated bases to the specific cysteine residue of the protein, thereby restoring DNA and resulting in its own inactivation. Alkyltransferases were first recognized in E. coli as part of the adaptive response to low doses of the methylating agent MNNG. Alkyltransferase activities were subsequently reported in other prokaryotes and eukaryotes. The protein has been identified, its function studied and its gene cloned ranging from bacteria through yeast to mammals. There was no report of alkylguanine-DNA alkyltransferase activity in plants so far. Nevertheless, in silico analysis of plant genomes enabled to identify several homologs of this enzyme in Arabidopsis and O. sativa suggesting that plants also posses this type of damage. Although C. reinhardtii similarly to higher plants seems to lack the alkyltransferase protein activity, in silico analysis of Chlamydomonas genome revealed the presence of the gene coding for DNA repair methyltransferase. The main goal of this presentation is to discuss results obtained from a detailed analysis of the role of alkyltransferase protein in C. reinhardtii. Our analysis revealed that the gene is expressed in Chlamydomonas cells. The gene was cloned and its role has been studied. This work was supported by grants by the Grant VEGA 1/0279/09.

e-mail address of presenting author: sevcovicova@fns.uniba.sk