H. Shi et al., A SPECIFIC RNA HAIRPIN LOOP STRUCTURE BINDS THE RNA RECOGNITION MOTIFS OF THE DROSOPHILA SR PROTEIN B52, Molecular and cellular biology, 17(5), 1997, pp. 2649-2657
B52, also known as SRp55, is a member of the Drosophila melanogaster S
R protein family, a group of nuclear proteins that are both essential
splicing factors and specific splicing regulators. Like most SR protei
ns, B52 contains two RNA recognition motifs in the N terminus and a C-
terminal domain rich in serine-arginine dipeptide repeats, Since B52 i
s an essential protein and is expected to play a role in splicing a su
bset of Drosophila pre-mRNAs, its function is likely to be mediated by
specific interactions with RNA. To investigate the RNA-binding specif
icity of B52, we isolated B52-binding RNAs by selection and amplificat
ion from a pool of random RNA sequences by using full length B52 prote
in as the target. These RNAs contained a conserved consensus motif tha
t constitutes the core of a secondary structural element predicted by
energy minimization, Deletion and substitution mutations defined the B
52-binding site on these RNAs as a hairpin loop structure covering abo
ut 20 nucleotides, which was confirmed by structure-specific enzymatic
probing, Finally, we demonstrated that both RNA recognition motifs of
B52 are required for RNA binding, while the RS domain is not involved
in this interaction.