a 5'-end triphospho-guanosine-ribonucleotide-snRNA + S-adenosyl-L-methionine => a 5'-end methyltriphosphate-guanosine-ribonucleotide-snRNA + S-adenosyl-L-homocysteine
a 5'-end triphospho-guanosine-ribonucleotide-snrna + s-adenosyl-l-methionine => a 5'-end methyltriphosphate-guanosine-ribonucleotide-snrna + s-adenosyl-l-homocysteine