The primary nucleotide sequence of nuclear U-2 ribonucleic acid. The 5'-terminal portion of the molecule

The nuclear U-2 RNA which is highly modified (Reddy, R., Ro Choi, T.S., Henning, D., Shibata, H., Choi, Y.C., and Busch H. (1972) J. Biol. Chem. 247, 7245-7250) contains 13 pseudouridylic acid residues, 10 2'-O-methylated nucleotides and two modified bases including N-2,2, 7-trimethyl guanylic acid in its 5'-terminal portion (69 nucleotides). With the determination of this sequence and its overlap with the 3' portion of the molecule (nucleotides 70 to 196), the over-all nucleotide sequence of this RNA is:(see article). The concentration of modified nucleotides in its 5' portion is greater than for any RNA sequenced thus far.