The tRNA N2,N2-dimethylguanosine-26 methyltransferase encoded by gene trm1 increases efficiency of suppression of an ochre codon in Schizosaccharomyces pombe.
In the majority of eukaryotic tRNAs, the guanosine at position 26 is modified by a dimethyl group, but so far a function of this modification has not been detected. We isolated the Schizosaccharomyces pombe gene, trm1, encoding the tRNA N2, N2-dimethylguanosine-26 methyltransferase. Strains having the gene deleted completely lack N2,N2-dimethylguanosine. In strains carrying the weak ochre tRNA suppressor sup3-i, deletion of trm1 abolishes suppression indicating that the trm1 deletion acts as an antisuppressor mutation. The result suggests that in vivo N2, N2-dimethylguanosine-26 increases the capacity of the sup3-i serine tRNA to translate the UAA (ochre) codon.
Niederberger
C
C
Institute of General Microbiology, Baltzerstrasse 4, CH-3012, Bern, Switzerland.
Gräub
R
R
Costa
A
A
Desgrès
J
J
Schweingruber
M E
ME
D000483:Alleles; D000595:Amino Acid Sequence; D018389:Codon, Nonsense; D015723:Gene Library; D016153:Genes, Suppressor; D005838:Genotype; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D012343:RNA, Transfer / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012568:Schizosaccharomyces / Q000201:enzymology / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012359:tRNA Methyltransferases / Q000235:genetics / Q000502:physiology*
D018389:Codon, Nonsense; D012343:RNA, Transfer; C089041:N(2),N(2)-dimethylguanosine-26-methyltransferase; D012359:tRNA Methyltransferases