Associated component of the WMM complex, a complex that mediates N6-methyladenosine (m6A) methylation of mRNAs, a modification that plays a role in the efficiency of mRNA splicing and is required for sex determination (PubMed:27919077). Required for sex determination and dosage compensation via Sxl alternative splicing: m6A methylation acts as a key regulator of Sxl pre-mRNA and promotes female-specific alternative splicing of Sxl, which determines female physiognomy (PubMed:1695150, PubMed:27919077). M6A methylation is also required for neuronal functions (PubMed:27919077). Required for proper inclusion of regulated exons in Ubx transcripts, leading to isoforms Ia/b and IIa/b (PubMed:10101174). Component of the WMM complex, a N6-methyltransferase complex composed of a catalytic subcomplex, named MAC, and of an associated subcomplex, named MACOM (PubMed:27919077, PubMed:28675155, PubMed:29535189, PubMed:29555755). The MAC subcomplex is composed of Ime4/Mettl3 and Mettl14 (PubMed:29535189, PubMed:29555755). The MACOM subcomplex is composed of fl(2)d, Flacc/Xio, Hakai, vir, and, in some cases of nito (PubMed:27919077, PubMed:28675155, PubMed:29535189, PubMed:29555755). Interacts with vir and msk (PubMed:12444081). Part of a complex containing fl(2)d, Sxl and vir (PubMed:12444081). Ubiquitously expressed in early embryonic stages with enrichment in the neuroectoderm at later stages. Major. Minor. Belongs to the fl(2)d family.