S-adenosyl-L-methionine-dependent protein-arginine N-methyltransferase that catalyzes both the mono- and asymmetric (type I) dimethylation of the guanidino nitrogens of arginine residues in target proteins (By similarity). Asymmetrically dimethylates the polyadenylate-binding protein pab2, modulating pab2 oligomerization (PubMed:17213188). Interacts with pab2. Belongs to the class I-like SAM-binding methyltransferase superfamily. Protein arginine N-methyltransferase family.