The 8.1 kb chromosomal fragment partially suppressing the ogd1 mutation in Saccharomyces cerevisiae has been cloned. The molecular analysis revealed that its suppressor gene codes for a natural glutamine tRNA(CAG) and maps on chromosome XIII in the upstream region of the URA10 gene. The multicopy plasmids containing this tRNA gene also suppressed the standard trp1-1 amber mutation and conferred the sensitivity of yeast cells to paromomycin and increased temperature.