Originally from Cleveland, Ohio, Nathan is a third year graduate student at the Ohio State University. As a student in Dr. Jane Jackman’s lab, Nathan studies methyltransferase enzymes involved in tRNA modification and epigenetic regulation using classical biochemical approaches. His current goal is to understand the behavior of two methyltransferases; these behaviors will help to understand novel mechanisms a cell might use to respond to environmental stress, and will aid efforts to develop a novel anti-cancer drug. Nathan obtained his BS in Chemistry from Baldwin Wallace University, and would love to use the skills developed during his PhD to conduct research or teach classes at a similar small liberal arts university.
Cellular adaptation using the m1G9¬ tRNA modification and its catalyst, Trm10
It is well known that nature uses tRNA as a critical adapter molecule between nucleic acids and protein, but recent evidence from the field of tRNA modifications supports a broader role of tRNA. We hypothesize that, via these complex and universally-found modifications, nature also uses tRNA as a sensing system poised to link cellular metabolism and protein translation. To better understand this system, we study the function and mechanism of a broadly conserved family of tRNA modification enzymes with multiple homologs in Archaea and Eukarya, Trm10. Discovered in Saccharomyces cerevisiae, the Trm10 tRNA methyltransferase is responsible for the addition of a methyl group to the N-1 atom of 9th-position guanosine residues in tRNAs. We seek to determine the functional significance of the m1G9 added by Trm10, as well as how Trm10 distinguishes substrate tRNAs from its potential pool of substrates. To do this, we have explored Trm10’s substrate specificity by converting a Type II, non-substrate tRNA into a Type I-like substrate tRNA using domain-swapping mutations. Additionally, we used HPLC analysis of gross ribonucleoside hydrolysates derived from stressed, Trm10-deficient cells to assess the impact of m1G9 deficiency on other RNA modifications. Coupled with individual tRNA complementation assays, this allows us to assess the functional significance of the m1G9 modification.