Poster abstracts
Poster number 7 submitted by Isobel Bowles
Identification of a tRNA-specific function for the tRNA methyltransferase Trm10 in Saccharomyces cerevisiae
Isobel Bowles (Ohio State Biochemistry Program), Jane Jackman (OSU Chemistry and Biochemistry)
Abstract:
tRNA methyltransferase 10 (Trm10), first discovered in Saccharomyces cerevisiae (S. cerevisiae), methylates N1 of guanosine at the 9th position of tRNA molecules using methyl donor S-adenosyl methionine (SAM). Upon the deletion of TRM10, S. cerevisiae strains experience growth defects in the presence of antitumor drug 5-fluorouracil (5FU). We hypothesized that tRNA stability decreases with the lack of m1G9 in trm10Δ strains and that certain tRNA species are more reliant upon the presence of the methylated G9 nucleotide, as evident from different growth phenotypes observed upon tRNA overexpression. When Trm10 substrate tRNATrp is overexpressed in trm10Δ strains, growth hypersensitivity to 5FU is rescued, while overexpression of other tRNA species in S. cerevisiae do not display a growth rescue. Levels of tRNATrp decrease in trm10Δ strains compared to levels of substrate tRNAGly while overexpression of tRNATrp recovers levels of tRNATrp in trm10Δ strains. The specific role of the m1G9 tRNA modification is being investigated by analyzing mechanisms of tRNATrp breakdown in S. cerevisiae trm10Δ strains with 5FU while also analyzing tRNA abundance for multiple Trm10 substrate tRNAs in the presence and absence of 5FU. tRNA structures that correlate with active substrates are being determined with nuclease and chemical footprinting, as well as 2’ hydroxyl acylation analyzed by primer extension (SHAPE). Together these studies will provide further understanding of tRNA structural elements that promote methylation by Trm10.
Keywords: trna modification, m1G9, SHAPE