3'-cyclic phosphorylation of U6 snRNA leads to recruitment of recycling factor p110 through LSm proteins.
Pre-mRNA splicing proceeds through assembly of the spliceosome complex, catalysis, and recycling. During each cycle the U4/U6.U5 tri-snRNP is disrupted and U4/U6 snRNA base-pairing unwound, releasing separate post-spliceosomal U4, U5, and U6 snRNPs, which have to be recycled to the splicing-competent tri-snRNP. Previous work implicated p110--the human ortholog of the yeast Prp24 protein--and the LSm2-8 proteins of the U6 snRNP in U4/U6 recycling. Here we show in vitro that these proteins bind synergistically to U6 snRNA: Both purified and recombinant LSm2-8 proteins are able to recruit p110 protein to U6 snRNA via interaction with the highly conserved C-terminal region of p110. Furthermore, the presence of a 2',3'-cyclic phosphate enhances the affinity of U6 snRNA for the LSm2-8 proteins and inversely reduces La protein binding, suggesting a direct role of the 3'-terminal phosphorylation in RNP remodeling during U6 biogenesis.
Institute of Biochemistry, Justus-Liebig-University of Giessen, D-35392 Giessen, Germany.
Konstantin
K
Licht
Jan
J
Medenbach
Reinhard
R
Lührmann
Christian
C
Kambach
Albrecht
A
Bindereif
D000951:Antigens, Neoplasm; D001324:Autoantigens / Q000378:metabolism; D001483:Base Sequence; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D012326:RNA Splicing; D012342:RNA, Small Nuclear / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism; D000097585:SS-B Antigen
D000951:Antigens, Neoplasm; D001324:Autoantigens; D009687:Nuclear Proteins; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; C416530:SART3 protein, human; C405486:U6 small nuclear RNA