1. Academic Validation
  2. THUMPD3-TRMT112 is a m2G methyltransferase working on a broad range of tRNA substrates

THUMPD3-TRMT112 is a m2G methyltransferase working on a broad range of tRNA substrates

  • Nucleic Acids Res. 2021 Nov 18;49(20):11900-11919. doi: 10.1093/nar/gkab927.
Wen-Qing Yang 1 Qing-Ping Xiong 2 Jian-Yang Ge 1 Hao Li 1 Wen-Yu Zhu 1 Yan Nie 3 Xiuying Lin 4 Daizhu Lv 5 Jing Li 1 Huan Lin 4 Ru-Juan Liu 1
Affiliations

Affiliations

  • 1 School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
  • 2 CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai 200031, China.
  • 3 Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai 201210, China.
  • 4 State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, Haikou, China.
  • 5 Analysis and Testing Center, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
Abstract

Post-transcriptional modifications affect tRNA biology and are closely associated with human diseases. However, progress on the functional analysis of tRNA modifications in metazoans has been slow because of the difficulty in identifying modifying Enzymes. For example, the biogenesis and function of the prevalent N2-methylguanosine (m2G) at the sixth position of tRNAs in eukaryotes has long remained enigmatic. Herein, using a reverse genetics approach coupled with RNA-mass spectrometry, we identified that THUMP domain-containing protein 3 (THUMPD3) is responsible for tRNA: m2G6 formation in human cells. However, THUMPD3 alone could not modify tRNAs. Instead, multifunctional methyltransferase subunit TRM112-like protein (TRMT112) interacts with THUMPD3 to activate its methyltransferase activity. In the in vitro enzymatic assay system, THUMPD3-TRMT112 could methylate all the 26 tested G6-containing human cytoplasmic tRNAs by recognizing the characteristic 3'-CCA of mature tRNAs. We also showed that m2G7 of tRNATrp was introduced by THUMPD3-TRMT112. Furthermore, THUMPD3 is widely expressed in mouse tissues, with an extremely high level in the testis. THUMPD3-knockout cells exhibited impaired global protein synthesis and reduced growth. Our data highlight the significance of the tRNA: m2G6/7 modification and pave a way for further studies of the role of m2G in sperm tRNA derived fragments.

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