分子生物學(xué)2--rnaprocessing(完整版)
【正文】 (65 and 35 kDa subunits) to the pyrimidine tract (YYYY) and the AG dinucleotide of the upstream 339。 Posttranscriptional Gene Regulation (events) ?Processing ?Transport ?Localization ?RNA stability ?Translation ?Posttranslational modification and protein stability Anatomy of a Eukaryotic mRNA Anatomy of a eukaryotic mRNA RNA Processing ? Splicing ? Capping ? Polyadenylation ? Editing ? rRNA Maturation ? tRNA Maturation Splicing (The process by which introns are removed) ? Spliceosomal splicing (premRNA splicing) ? Selfsplicing Group I in some rRNAs Group II in some yeast and fungal mitochondrial transcripts ? Alternative splicing ? TranSplicing Spliceosomal cissplicing (premRNA splicing) ? History of discovery ? Overview of reaction mechanism Splicing signals in premRNAs Splicing via Two Transesterification Reactions SnRNPs assist in Splicing The spliceosomal splicing model WEAVER: FIG. Highly conserved sequences are indicated in red Consensus sequences at exonintron boundaries MECHANISM OF SPLICING OF EUKARYOTIC PREmRNA: AN OUTLINE CONSENSUS SEQUENCES AT 5’ SPLICE SITE, BRANCH SITE AND 5’ SPLICE SITE VERTEBRATES: 5’AG/GUAAGUintronYNCURAC(Y)nNAG/G3’ YEAST: 5’NN/GUAUGUintronUACUAACYAG/G3’ WEAVER: FIG. Analysis of RNA products formed in an in vitro splicing reaction. A nuclear extract from HeLa cells was incubated with a 497nucleotide radiolabeled RNA that contained portions of two exons (numbered 1 and 2) from human betaglobin mRNA separated by a 130nucleotide intron. After incubation for various times, the RNA was purified and subjected to electrophoresis and autoradiography. a snRNA(U1~U6) snRNP core proteins (., Sm) specific proteins Small Urich RNA (snRNA) are abundant in the nuclei Base pairing between snRNAs and premRNA ? U1: 539。exon prior to lariat formation. U6 exchanges base pairing from U4 to U2. RNA helicases facilitate these rearrangements. U2 snRNA U6 snRNA U5 premRNA The spliceosomal splicing model Weaver Fig Spliceosome ? Large RNAprotein plex in which premRNA undergoes cissplicing ? 4060 S particles ? Consists
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鄂ICP備17016276號(hào)-1