Arginine methyltransferase that can both catalyze the formation of omega-N monomethylarginine (MMA) and symmetrical dimethylarginine (sDMA) (By similarity). Specifically mediates the symmetrical dimethylation of arginine residues in the small nuclear ribonucleoproteins SmD1 and SmD3. Required for arginine symmetrical dimethylation of piwi family proteins, piwi, aub and AGO3, during germline development. Required during oogenesis for pole cell formation in the pathway controlled by oskar (osk) and for abdominal segments during early embryogenesis. Involved in nanos (nos) and germ cell mRNAs localization. Interacts with vls. Expressed only in ovaries. Expressed both maternally and zygotically. Expressed from stage 3 egg chambers onward, becoming restricted to the cortex of the oocytes at stage 10. Evenly distributed in preblastoderm embryos. Flies are viable and do not display neuromuscular dysfunctions. Strong synthetic lethal phenotype in the presence of a hypomorphic Smn mutation. Belongs to the class I-like SAM-binding methyltransferase superfamily. Protein arginine N-methyltransferase family.