U1_snRNA
U1 is a small nuclear RNA (snRNA) component of the spliceosome (involved in pre-mRNA splicing). Its 5' end forms complementary base pairs with the 5' splice junction, thus defining the 5' donor site of an intron. There are significant differences in sequence and secondary structure between metazoan and yeast U1 snRNAs, the latter being much longer (568 nucleotides as compared to 164 nucleotides in human). Nevertheless, secondary structure predictions suggest that all U1 snRNAs share a 'common core' consisting of helices I, II, the proximal region of III, and IV.
SO:0000274
snRNA
is_a
U1 small nuclear RNA
exact
U1 snRNA
exact
small nuclear RNA U1
exact
snRNA U1
exact