Methylates (mono and asymmetric dimethylation) the guanidino nitrogens of arginyl residues present in a glycine and arginine-rich domain. Type I arginine methyltransferase active on both histones and non-histone proteins. Required for leaves and flowers development. Mediates the methylation of MBD7 and MED36A. L-arginyl-[protein] + 2 S-adenosyl-L-methionine = 2 H(+) + N(omega),N(omega)-dimethyl-L-arginyl-[protein] + 2 S-adenosyl-L-homocysteine Interacts with PRMT12, MBD7 and FIB2. Excluded from nucleolus. Reduced levels of proteins with asymmetrically dimethylated arginines. Altered leaf morphology and development (curled leaves), multiple rosettes with an increased number of leaves, delayed flowering, disturbed inflorescence morphology, increased sterility. Belongs to the class I-like SAM-binding methyltransferase superfamily. Protein arginine N-methyltransferase family.