Genetic evidence for base pairing between U2 and U6 snRNA in mammalian mRNA splicing.
Removal of introns from eukaryotic nuclear messenger RNA precursors is catalysed by a large ribonucleoprotein complex called the spliceosome, which consists of four small nuclear ribonucleoprotein particles (U1, U2, U5, and U4/U6 snRNPs) and auxiliary protein factors. We have begun a genetic analysis of mammalian U2 snRNA by making second-site mutations in a suppressor U2 snRNA. Here we find that several mutations in the 5' end of U2 (nucleotides 3-8) are deleterious and that one of these can be rescued by compensatory base changes in the 3' end of U6 (nucleotides 92-95). The results demonstrate genetically that the base-pairing interaction between U2 (nucleotides 3-11) and U6 snRNA (nucleotides 87-95), originally proposed on the basis of psoralen photocrosslinking experiments, can influence the efficiency of mRNA splicing in mammals. The U2/U6 interaction in yeast, however, is fairly tolerant to mutation (D.J. Field and J.D. Friesen, personal communication), emphasizing the potential for facultative RNA interactions within the spliceosome.
Datta
B
B
Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06510.
Weiner
A M
AM
D001482:Base Composition; D001483:Base Sequence; D016153:Genes, Suppressor; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010957:Plasmids; D012322:RNA Precursors / Q000235:genetics; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics*; D012342:RNA, Small Nuclear / Q000235:genetics* / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D017411:Ribonucleoproteins, Small Nuclear; D014162:Transfection
D012322:RNA Precursors; D012333:RNA, Messenger; D012342:RNA, Small Nuclear; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear