This entry represents tRNA (guanine-N(7)-)-methyltransferase non-catalytic subunit Trm82 and its homologues, wuho from flies and WDR4 from humans. In Saccharomyces cerevisiae, Trm82 is the non-catalytic subunit of the tRNA methyltransferase complex which consists of Trm8 and Trm82 [, ]. It is essential for the enzyme activity and may function in regulating the the Trm8 protein []. In humans, WDR4 forms the tRNA methyltransferase complex with METTL1 (Trm8 homologue). It is required to stabilise and induce conformational changes of the catalytic subunit METTL1 []. It is required for the formation of N7-methylguanine at position 46 (m7G46) in tRNA [, ]and also for the formation of N7-methylguanine at internal sites in a subset of mRNAs []. WDR4 is also involved in the methylation of a specific subset of miRNAs, such as let-7 []. Independently of METTL1, it also plays a role in genome stability: localizes at the DNA replication site and regulates endonucleolytic activities of FEN1 [].
This entry represents the eukaryotic tRNA (guanine-N-7) methyltransferases catalytic subunit Trm8, and its homologue, such as METTL1 from humans []. In Saccharomyces cerevisiae, it forms the tRNA methyltransferase complex with Trm82 (WDR4 homologue in humans). This enzyme catalyses the formation of N(7)-methylguanine at position 46 (m7G46) in tRNA, a modification required to maintain stability of tRNAs; its absence resulting in tRNA decay. Both the D-stem and T-stem structures of tRNAs are required for efficient methyltransferase activity [, , ]. The function of Trm8 is regulated by Trm82 [].
