Funding Organization(s): Ministry of Education, Culture, Sports, Science and Technology (Japan), Japan Society for the Promotion of Science (JSPS), Japan Science and Technology
Transfer RNA (tRNA) modifications are critical for protein synthesis. Queuosine (Q), a 7-deaza-guanosine derivative, is present in tRNA anticodons. In vertebrate tRNAs for Tyr and Asp, Q is further glycosylated with galactose and mannose to generate galQ and manQ, respectively. However, biogenesis and physiological relevance of Q-glycosylation remain poorly understood. Here, we biochemically identified two RNA glycosylases, QTGAL and QTMAN, and successfully reconstituted Q-glycosylation of tRNAs using nucleotide diphosphate sugars. Ribosome profiling of knockout cells revealed that Q-glycosylation slowed down elongation at cognate codons, UAC and GAC (GAU), respectively. We also found that galactosylation of Q suppresses stop codon readthrough. Moreover, protein aggregates increased in cells lacking Q-glycosylation, indicating that Q-glycosylation contributes to proteostasis. Cryo-EM of human ribosome-tRNA complex revealed the molecular basis of codon recognition regulated by Q-glycosylations. Furthermore, zebrafish qtgal and qtman knockout lines displayed shortened body length, implying that Q-glycosylation is required for post-embryonic growth in vertebrates.
Organizational Affiliation:
Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan.
Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa 230-0045, Japan.
RNA System Biochemistry Laboratory, Cluster for Pioneering Research, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8561, Japan.
RNA System Biochemistry Laboratory, Cluster for Pioneering Research, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Faculty of Life Sciences, Kyoto Sangyo University, Kita-ku, Kyoto 603-8555, Japan.
Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa 230-0045, Japan; Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan.
Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa 230-0045, Japan.
Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan. Electronic address: t_suzuki@med.u-ryukyu.ac.jp.
Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Tokyo 113-8656, Japan. Electronic address: ts@chembio.t.u-tokyo.ac.jp.
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