May have S-adenosyl-L-methionine-dependent methyl-transferase activity. Expressed in testis. Low expression in 12-day-old testes when the majority of advanced cells are in zygonema, but increased by 14 to 18 days of age when most spermatocytes are in pachynema. Male infertility. A mutation which results in the conversion of codon 333, encoding glutamine, into a premature stop codon is detected in chemically-induced mutant Ste5Jcs1 mice; these mice are characterized by sperm motility defects and infertility. Belongs to the class I-like SAM-binding methyltransferase superfamily. RsmB/NOP family.