Required for the formation of N(7)-methylguanine at position 46 (m7G46) in tRNA. In the complex, it is required to stabilize and induce conformational changes of the catalytic subunit. Required during gametogenesis. tRNA modification; N(7)-methylguanine-tRNA biosynthesis. Forms a heterodimer with the catalytic subunit. Localized to the nuclei of nurse cells, follicle cells and oocytes at early stages, from germarium to stage 4 egg chambers. Also present in the nuclei of spermatocytes and in the apical cells of the testes. Belongs to the WD repeat TRM82 family.