Required Elements in tRNA for Methylation by the Eukaryotic tRNA (Guanine- N 2 -) Methyltransferase (Trm11-Trm112 Complex)

• Published in: International journal of molecular sciences 2022-04, Vol.23 (7), p.4046
• Main Authors: Nishida, Yu, Ohmori, Shiho, Kakizono, Risa, Kawai, Kunpei, Namba, Miyu, Okada, Kazuki, Yamagami, Ryota, Hirata, Akira, Hori, Hiroyuki
• Format: Article
• Language: English
• Subjects: Crystal structure; Cytoplasm; E coli; Gene deletion; Guanine; Guanine - metabolism; Methylation; Methyltransferases - metabolism; Nucleic Acid Conformation; Proteins; RNA, Transfer - genetics; RNA, Transfer - metabolism; RNA, Transfer, Val - metabolism; Saccharomyces cerevisiae; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Transcription; Transfer RNA; tRNA; tRNA Methyltransferases - genetics; tRNA Methyltransferases - metabolism; Variable region
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms23074046

The Trm11 and Trm112 complex (Trm11-Trm112) methylates the 2-amino group of guanosine at position 10 in tRNA and forms -methylguanosine. To determine the elements required in tRNA for methylation by Trm11-Trm112, we prepared 60 tRNA transcript variants and tested them for methylation by Trm11-Trm112. The results show that the precursor tRNA is not a substrate for Trm11-Trm112. Furthermore, the CCA terminus is essential for methylation by Trm11-Trm112, and Trm11-Trm112 also only methylates tRNAs with a regular-size variable region. In addition, the G10-C25 base pair is required for methylation by Trm11-Trm112. The data also demonstrated that Trm11-Trm112 recognizes the anticodon-loop and that U38 in tRNA acts negatively in terms of methylation. Likewise, the U32-A38 base pair in tRNA negatively affects methylation. The only exception in our in vitro study was tRNA . Our experiments showed that the tRNA transcript was slowly methylated by Trm11-Trm112. However, position 10 in this tRNA was reported to be unmodified G. We purified tRNA from wild-type and gene deletion strains and confirmed that a portion of tRNA is methylated by Trm11-Trm112 in . Thus, our study explains the m G10 modification pattern of all class I tRNAs and elucidates the Trm11-Trm112 binding sites.