In vitro interaction of U2 snRNA with cytoplasmic 6S protein complexes

Abstract

Interactions of U2 snRNA with anti-Sin precipitable proteins in RNA-free cytoplasmic complexes were analyzed. U2 snRNA was found to bind specifically with proteins in the 6S complexes but not in the 20S complexes. The binding activity was preserved using U2 snRNA having a mutated Sm binding site. Label-transfer experiments indicate that snRNA makes direct contact with anti-Sm precipitable proteins in the 6S fraction with apparent molecular mass of about 16 kDa. These data corroborate that proteins in the 6S core particle are the first to interact with snRNA, and suggest that the proteins recognize snRNA structures in addition to the Sm site.

Purification and crystallization of spliceosomal snRNPs

“…B/B' and D3 as well as D1 and D2 have been shown to interact with each other by coexpression studies and crystal structures (Kambach et al, 1999a;Raker et al, 1999). The relative positions of E, F and G can be concluded from immunoprecipitation assays and yeast two-hybrid studies (Camasses et al, 1998;Fury and Andersen, 1997;Fury et al, 1999). The fold of the Sm motifs is an anti-parallel five stranded β-sheet, furthermore Clashes, which occurred mainly on the termini were removed manually by deleting the respective residues (Kambach et al, 1999b;Törö et al, 2001;Collins and Guthrie, 2000) .…”