ジャーナル: Nature / 年: 2024 タイトル: Mechanism for the initiation of spliceosome disassembly. 著者: Matthias K Vorländer / Patricia Rothe / Justus Kleifeld / Eric D Cormack / Lalitha Veleti / Daria Riabov-Bassat / Laura Fin / Alex W Phillips / Luisa Cochella / Clemens Plaschka / 要旨: Precursor-mRNA (pre-mRNA) splicing requires the assembly, remodelling and disassembly of the multi-megadalton ribonucleoprotein complex called the spliceosome. Recent studies have shed light on ...Precursor-mRNA (pre-mRNA) splicing requires the assembly, remodelling and disassembly of the multi-megadalton ribonucleoprotein complex called the spliceosome. Recent studies have shed light on spliceosome assembly and remodelling for catalysis, but the mechanism of disassembly remains unclear. Here we report cryo-electron microscopy structures of nematode and human terminal intron lariat spliceosomes along with biochemical and genetic data. Our results uncover how four disassembly factors and the conserved RNA helicase DHX15 initiate spliceosome disassembly. The disassembly factors probe large inner and outer spliceosome surfaces to detect the release of ligated mRNA. Two of these factors, TFIP11 and C19L1, and three general spliceosome subunits, SYF1, SYF2 and SDE2, then dock and activate DHX15 on the catalytic U6 snRNA to initiate disassembly. U6 therefore controls both the start and end of pre-mRNA splicing. Taken together, our results explain the molecular basis of the initiation of canonical spliceosome disassembly and provide a framework to understand general spliceosomal RNA helicase control and the discard of aberrant spliceosomes.
#1: ジャーナル: Science / 年: 2019 タイトル: A human postcatalytic spliceosome structure reveals essential roles of metazoan factors for exon ligation. 著者: Sebastian M Fica / Chris Oubridge / Max E Wilkinson / Andrew J Newman / Kiyoshi Nagai / 要旨: During exon ligation, the spliceosome recognizes the 3'-splice site (3'SS) of precursor messenger RNA (pre-mRNA) through non-Watson-Crick pairing with the 5'SS and the branch adenosine, in a ...During exon ligation, the spliceosome recognizes the 3'-splice site (3'SS) of precursor messenger RNA (pre-mRNA) through non-Watson-Crick pairing with the 5'SS and the branch adenosine, in a conformation stabilized by Prp18 and Prp8. Here we present the 3.3-angstrom cryo-electron microscopy structure of a human postcatalytic spliceosome just after exon ligation. The 3'SS docks at the active site through conserved RNA interactions in the absence of Prp18. Unexpectedly, the metazoan-specific FAM32A directly bridges the 5'-exon and intron 3'SS of pre-mRNA and promotes exon ligation, as shown by functional assays. CACTIN, SDE2, and NKAP-factors implicated in alternative splicing-further stabilize the catalytic conformation of the spliceosome during exon ligation. Together these four proteins act as exon ligation factors. Our study reveals how the human spliceosome has co-opted additional proteins to modulate a conserved RNA-based mechanism for 3'SS selection and to potentially fine-tune alternative splicing at the exon ligation stage.
1: PRKR-interacting protein 1 2: U2 snRNA 3: Splicing factor ESS-2 homolog 32: Protein FAM32A 5: U5 snRNA 50: Protein FAM50A 56: STING ER exit protein 6: U6 snRNA 7: Eukaryotic initiation factor 4A-III 8: RNA-binding protein 8A 9: Protein mago nashi homolog A: Pre-mRNA-processing-splicing factor 8 B: U5 small nuclear ribonucleoprotein 200 kDa helicase C: 116 kDa U5 small nuclear ribonucleoprotein component D: Pre-mRNA-splicing factor ISY1 homolog E: U5 small nuclear ribonucleoprotein 40 kDa protein EX: Exon F: Splicing factor Cactin H: Pre-mRNA-splicing factor CWC22 homolog I: Pre-mRNA-splicing factor SYF1 IN: INTRON J: Crooked neck-like protein 1 K: Pre-mRNA-splicing factor SPF27 L: Cell division cycle 5-like protein M: Pre-mRNA-splicing factor SYF2 N: Protein BUD31 homolog NO: Nitric oxide synthase-interacting protein O: Pre-mRNA-splicing factor RBM22 P: Spliceosome-associated protein CWC15 homolog Q: Intron-binding protein aquarius R: SNW domain-containing protein 1 S: Peptidyl-prolyl cis-trans isomerase-like 1 SR: Serine/arginine repetitive matrix protein 2 T: Pleiotropic regulator 1 U: Pre-mRNA-splicing factor SLU7 V: ATP-dependent RNA helicase DHX8 W: Pre-mRNA-processing factor 17 X: Splicing regulator SDE2 Z: Coiled-coil domain-containing protein 12 a: Small nuclear ribonucleoprotein Sm D3 b: Small nuclear ribonucleoprotein-associated proteins B and B' c: Small nuclear ribonucleoprotein Sm D1 d: Small nuclear ribonucleoprotein Sm D2 e: Small nuclear ribonucleoprotein E f: Small nuclear ribonucleoprotein F g: Small nuclear ribonucleoprotein G h: Small nuclear ribonucleoprotein Sm D3 i: Small nuclear ribonucleoprotein-associated proteins B and B' j: Small nuclear ribonucleoprotein Sm D1 k: Small nuclear ribonucleoprotein Sm D2 l: Small nuclear ribonucleoprotein E m: Small nuclear ribonucleoprotein F n: Small nuclear ribonucleoprotein G o: U2 small nuclear ribonucleoprotein A' p: U2 small nuclear ribonucleoprotein B'' q: Pre-mRNA-processing factor 19 r: Pre-mRNA-processing factor 19 s: Pre-mRNA-processing factor 19 t: Pre-mRNA-processing factor 19 w: Peptidylprolyl isomerase domain and WD repeat-containing protein 1 x: Splicing factor C9orf78 y: Peptidyl-prolyl cis-trans isomerase E z: NF-kappa-B-activating protein ヘテロ分子
分子量: 105646.578 Da / 分子数: 1 / 由来タイプ: 天然 / 由来: (天然) Homo sapiens (ヒト) / 参照: UniProt: Q9HCG8
#20: タンパク質
Pre-mRNA-splicingfactorSYF1 / Protein HCNP / XPA-binding protein 2
分子量: 100148.711 Da / 分子数: 1 / 由来タイプ: 天然 / 由来: (天然) Homo sapiens (ヒト) / 参照: UniProt: Q9HCS7
#23: タンパク質
Pre-mRNA-splicingfactorSPF27 / Breast carcinoma-amplified sequence 2 / DNA amplified in mammary carcinoma 1 protein / Spliceosome- ...Breast carcinoma-amplified sequence 2 / DNA amplified in mammary carcinoma 1 protein / Spliceosome-associated protein SPF 27
分子量: 26163.420 Da / 分子数: 1 / 由来タイプ: 天然 / 由来: (天然) Homo sapiens (ヒト) / 参照: UniProt: O75934