Non-catalytic component of a methyltransferase complex required for the formation of N(7)-methylguanine in a subset of RNA species, such as tRNAs, mRNAs and microRNAs (miRNAs) (PubMed:12403464, PubMed:31031084, PubMed:31031083). In the methyltransferase complex, it is required to stabilize and induce conformational changes of the catalytic subunit (PubMed:12403464). Required for the formation of N(7)-methylguanine at position 46 (m7G46) in tRNA (PubMed:12403464, PubMed:31031084). Also required for the formation of N(7)-methylguanine at internal sites in a subset of mRNAs (PubMed:31031084). Also required for methylation of a specific subset of miRNAs, such as let-7 (PubMed:31031083). Independently of METTL1, also plays a role in genome stability: localizes at the DNA replication site and regulates endonucleolytic activities of FEN1 (PubMed:26751069). tRNA modification; N(7)-methylguanine-tRNA biosynthesis. Forms a heterodimer with the catalytic subunit METTL1 (PubMed:12403464, PubMed:26751069). Interacts with FEN1; the interaction is direct (PubMed:26751069). Localizes at the site of nascent DNA synthesis. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Belongs to the WD repeat TRM82 family.