label: an N(7)-methylguanosine in mRNA + S-adenosyl-L-homocysteine => a guanosine in mRNA + S-adenosyl-L-methionine
label_lc: an n(7)-methylguanosine in mrna + s-adenosyl-l-homocysteine => a guanosine in mrna + s-adenosyl-l-methionine