Direct binding of small nuclear ribonucleoprotein G to the Sm site of small nuclear RNA. Ultraviolet light cross-linking of protein G to the AAU stretch within the Sm site (AAUUUGUGG) of U1 small nuclear ribonucleoprotein reconstituted in vitro.

摘要: The major small nuclear ribonucleoproteins (snRNPs) U1, U2, U5 and U4/U6 participate in the splicing of pre-mRNA. U4 RNAs share a highly conserved sequence motif PuA(U)nGPu, termed Sm site, which is normally flanked by two hairpin loops. site provides binding for group common proteins, B', B, D1, D2, D3, E, F G, are shared spliceosomal snRNPs. We have investigated ability snRNP proteins to recognize snRNA using ultraviolet light-induced RNA-protein cross-linking within U1 particles. particles, reconstituted vitro, contained labelled with 32P. Cross-linking protein this occurred only presence single-stranded stretch that makes up site. Characterization cross-linked one two-dimensional gel electrophoresis indicated G had become snRNA. This was confirmed specific immunoprecipitation complex an anti-G antiserum. cross-link located on fingerprint analysis RNases T1 A; demonstrated has been AAU 5'-terminal half (AAUUUGUGG). These results suggest may be involved direct recognition