Domains of human U4atac snRNA required for U12-dependent splicing in vivo.
U4atac snRNA forms a base-paired complex with U6atac snRNA. Both snRNAs are required for the splicing of the minor U12-dependent class of eukaryotic nuclear introns. We have developed a new genetic suppression assay to investigate the in vivo roles of several regions of U4atac snRNA in U12-dependent splicing. We show that both the stem I and stem II regions, which have been proposed to pair with U6atac snRNA, are required for in vivo splicing. Splicing activity also requires U4atac sequences in the 5' stem-loop element that bind a 15.5 kDa protein that also binds to a similar region of U4 snRNA. In contrast, mutations in the region immediately following the stem I interaction region, as well as a deletion of the distal portion of the 3' stem-loop element, were active for splicing. Complete deletion of the 3' stem-loop element abolished in vivo splicing function as did a mutation of the Sm protein binding site. These results show that the in vivo sequence requirements of U4atac snRNA are similar to those described previously for U4 snRNA using in vitro assays and provide experimental support for models of the U4atac/U6atac snRNA interaction.
Shukla
Girish C
GC
Department of Molecular Biology, Lerner Research Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
Cole
Andrea J
AJ
Dietrich
Rosemary C
RC
Padgett
Richard A
RA
D001324:Autoantigens; D001483:Base Sequence; D001665:Binding Sites; D006801:Humans; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D022821:RNA Splice Sites / Q000235:genetics; D012326:RNA Splicing; D012342:RNA, Small Nuclear / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017411:Ribonucleoproteins, Small Nuclear / Q000378:metabolism*; D017381:Spliceosomes / Q000235:genetics / Q000378:metabolism; D055517:snRNP Core Proteins
D001324:Autoantigens; D022821:RNA Splice Sites; D012342:RNA, Small Nuclear; D017411:Ribonucleoproteins, Small Nuclear; C552126:U11-U12 small nuclear ribonucleoprotein; C405482:U4 small nuclear RNA; C405486:U6 small nuclear RNA; D055517:snRNP Core Proteins