Wild-type U1 RNA and 128 pre-mRNA 22.4 The spliceosome Normal splicing contains snRNAs CAUUCAU5 exon G U GA GG intron 3' 128 adenovirus splice site Figure 22.9 Wild-type U1 snRNA and mutant 12S pre-mRNA Mutations that No splicing abolish function of the5￠splicing site 5'exon GU G AA U intron 3 can be suppressed by mutant splice site compensating Mutant U1 snRNA and mutant 12S RNA Splicing restored mutations in U1 snRNA that restore base pairing. exon GU G AA U intron 3 清菜大当
Figure 22.9 Mutations that abolish function of the 5￠ splicing site can be suppressed by compensating mutations in U1 snRNA that restore base pairing. 22.4 The spliceosome contains snRNAs
Intron Exon UACUAACPY-AG 22.4 The Left Branch Pytract Right consasus site consensus spliceosome ASF/SF2 UACUAAC Py-AG contains snRNAs Ecomplex U1 binds 5'spice site U1 ATP hydrolyzed L2AF binds pyimidine tra d Figure 22.10 The ●AS F/SF2 Py-AG. Acom plex U2 binds branch site splicing reaction ○U2AF proceeds through Bl complex U5/4/6 tri mer binds discrete stages in U5 h能82 natate which spliceosome U6 U4 E2 complex U1 is released U5 shitts from exon to intra formation involves U6 bindsat 5'splce site the interaction of C1 complex U4 is released components that U6/U2 catay zes transeserificatior U5 binds exon at 3'splice site recognize the 'site cleaed lariat tamed C2 complex consensus UACUAAC U2/5/6 rem ain boundto lariat 3'site cleaved exonsligated sequences. GU- UACUAAC-Py-AG Spliced RNA is released 清苇大兰 Lariat debranched
Figure 22.10 The splicing reaction proceeds through discrete stages in which spliceosome formation involves the interaction of components that recognize the consensus sequences. 22.4 The spliceosome contains snRNAs