U2_snRNA
U2 is a small nuclear RNA (snRNA) component of the spliceosome (involved in pre-mRNA splicing). Complementary binding between U2 snRNA (in an area lying towards the 5' end but 3' to hairpin I) and the branchpoint sequence (BPS) of the intron results in the bulging out of an unpaired adenine, on the BPS, which initiates a nucleophilic attack at the intronic 5' splice site, thus starting the first of two transesterification reactions that mediate splicing.
SO:0000274
snRNA
is_a
U2 small nuclear RNA
exact
U2 snRNA
exact
small nuclear RNA U2
exact
snRNA U2
exact