title: Recycling of the U12-type spliceosome requires p110, a component of the U6atac snRNP.
abstract: U12-dependent introns are spliced by the so-called minor spliceosome, requiring the U11, U12, and U4atac/U6atac snRNPs in addition to the U5 snRNP. We have recently identified U6-p110 (SART3) as a novel human recycling factor that is related to the yeast splicing factor Prp24. U6-p110 transiently associates with the U6 and U4/U6 snRNPs during the spliceosome cycle, regenerating functional U4/U6 snRNPs from singular U4 and U6 snRNPs. Here we investigated the involvement of U6-p110 in recycling of the U4atac/U6atac snRNP. In contrast to the major U6 and U4/U6 snRNPs, p110 is primarily associated with the U6atac snRNP but is almost undetectable in the U4atac/U6atac snRNP. Since p110 does not occur in U5 snRNA-containing complexes, it appears to be transiently associated with U6atac during the cycle of the minor spliceosome. The p110 binding site was mapped to U6 nucleotides 38 to 57 and U6atac nucleotides 10 to 30, which are highly conserved between these two functionally related snRNAs. With a U12-dependent in vitro splicing system, we demonstrate that p110 is required for recycling of the U4atac/U6atac snRNP.
authors.affiliation: Institut für Biochemie, Justus-Liebig-Universität Giessen, D-35392 Giessen, Germany.
authors.forename: Andrey
authors.initials: A
authors.lastname: Damianov
authors.forename: Silke
authors.initials: S
authors.lastname: Schreiner
authors.forename: Albrecht
authors.initials: A
authors.lastname: Bindereif
mesh_terms: D000951:Antigens, Neoplasm / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological; D008969:Molecular Sequence Data; D011485:Protein Binding; D012342:RNA, Small Nuclear / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017411:Ribonucleoproteins, Small Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017381:Spliceosomes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000951:Antigens, Neoplasm; D012342:RNA, Small Nuclear; D016601:RNA-Binding Proteins; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; D017411:Ribonucleoproteins, Small Nuclear; C416530:SART3 protein, human; C552126:U11-U12 small nuclear ribonucleoprotein; C405482:U4 small nuclear RNA; C405486:U6 small nuclear RNA