from the total of 37 ribose and 6 base-methyl groups found in 26-s rrna , the two copies of the base-methylated nucleoside m3u as well as the doubly methylated sequence um-gm psi are not yet present in 37-s rna , the predominant common precursor of 26-s and 17-s rrna .
C0035668
rna
C0035701
rrna