Trans-splicing RNA I RNA I exon 1 exon 2 5′ GU AAG 3 G AAG 3′ OH Figure 13-5 G AAg Not a lariat 5 3 Copyright o 2004 Pearson Education, Inc, publishing as Benjamin Cummings
Trans-splicing Figure 13-5 Not a lariat
CHATER 13 RNA Splicing Topic 2 THE SPLICESOME MACHINERY
Topic 2 THE SPLICESOME MACHINERY CHAPTER 13 RNA Splicing
RNA splicing is carried out by a o large complex called spliceosome a The above described splicing of 8 introns from pre-mRNA are mediated by the spliceosome. o The spliceosome comprises about 150 proteins and 5 SnRNAs 己■ Many functions of the spliceosome are carried out by its RNA components
RNA splicing is carried out by a large complex called spliceosome ◼ The above described splicing of introns from pre-mRNA are mediated by the spliceosome. ◼ The spliceosome comprises about 150 proteins and 5 snRNAs. ◼ Many functions of the spliceosome are carried out by its RNA components. The spliceosome machinery
a The five RNAs (U1 U2,U4, U5, and 06, 100-300 nt)are called small nuclear RNAS (snRNAS). The complexes of snRNA and proteins are called small nuclear ribonuclear proteins (snRNP pronounces“ Snurps”) a The spliceosome is the largest snRNP, and the exact makeup differs at different stages of the splicing reaction
◼ The five RNAs (U1, U2, U4, U5, and U6, 100-300 nt) are called small nuclear RNAs (snRNAs). ◼ The complexes of snRNA and proteins are called small nuclear ribonuclear proteins (snRNP, pronounces “snurps”). ◼ The spliceosome is the largest snRNP, and the exact makeup differs at different stages of the splicing reaction
a Three roles of snRNPs in splicing 1. Recognizing the 5, splice site and the branch site 2. Bringing those sites together. 3. Catalyzing (or helping to catalyze) the RNa cleavage. RNA-RNA, RNA-protein and protein-protein interactions are all important during splicing
◼ Three roles of snRNPs in splicing 1. Recognizing the 5’ splice site and the branch site. 2. Bringing those sites together. 3. Catalyzing (or helping to catalyze) the RNA cleavage. RNA-RNA, RNA-protein and protein-protein interactions are all important during splicing