tRNA (guanine-N(7)-)-methyltransferase, also known as Methyltransferase-like protein 1, tRNA (m7G46)-methyltransferase and METTL1, is a nucleus protein which belongs to themethyltransferase superfamily and TrmB family. METTL1 gene, has been identified by its sequence similarity to the yeast ORF YDL21w. The human cDNA and the genomic structure of METTL1 have been analyzed. The transcript contains 1292 nucleotides and codes for a protein of 276 amino acids. The METTL1 gene product shows high sequence similarities to putative proteins from mouse, Drosophila melanogaster, Arabidopsis thaliana, Caenorhabditis elegans, and yeast (39.8% identity between all six species). Computer analyses of the deduced protein sequence reveal two highly conserved amino acid motifs, one of which is typical for methyltransferases. Both motifs are also present in hypothetical proteins from eubacteria. Disruption of the homologous yeast ORF YDL21w shows that the gene is at least not essential for vegetative growth in Saccharomyces cerevisiae.