Catalytic component of METTL1-WDR4 methyltransferase complex that mediates the formation of N(7)-methylguanine in a subset of RNA species, such as tRNAs, mRNAs and microRNAs (miRNAs) (   ). Catalyzes the formation of N(7)-methylguanine at position 46 (m7G46) in a large subset of tRNAs that contain the 5'-RAGGU-3' motif within the variable loop (  , ). M7G46 interacts with C13-G22 in the D-loop to stabilize tRNA tertiary structure and protect tRNAs from decay (, ). Also acts as a methyltransferase for a subset of internal N(7)-methylguanine in mRNAs (, ). Internal N(7)-methylguanine methylation of mRNAs in response to stress promotes their relocalization to stress granules, thereby suppressing their translation (, ). Also methylates a specific subset of miRNAs, such as let-7 . N(7)-methylguanine methylation of let-7 miRNA promotes let-7 miRNA processing by disrupting an inhibitory secondary structure within the primary miRNA transcript (pri-miRNA) . Acts as a regulator of embryonic stem cell self-renewal and differentiation (By similarity).
Subcellular locations: Nucleus
Ubiquitous.