Arginine methyltransferase that specifically catalyzes the formation of omega-N monomethylarginine (MMA). Has activity toward multiple substrates in vitro. Able to mediate the arginine methylation of histones and myelin basic protein (MBP) in vitro; the relevance of such results is however unclear in vivo. Present in large multiprotein complexes. Expressed during both bloodstream (BF) and procyclic insect (PF) life cycle stages. Belongs to the class I-like SAM-binding methyltransferase superfamily. Protein arginine N-methyltransferase family. PRMT7 subfamily. Compared to PRMT7 orthologs in other metazoans, it is shorter and lacks the C-terminal part.