scholarly journals SPF30 Is an Essential Human Splicing Factor Required for Assembly of the U4/U5/U6 Tri-small Nuclear Ribonucleoprotein into the Spliceosome

2001 ◽  
Vol 276 (33) ◽  
pp. 31142-31150 ◽  
Author(s):  
Juri Rappsilber ◽  
Paul Ajuh ◽  
Angus I. Lamond ◽  
Matthias Mann
Keyword(s):  
Splicing Factor ◽  
Small Nuclear Ribonucleoprotein ◽  
Nuclear Ribonucleoprotein

scholarly journals Assembly of the U5 snRNP component PRPF8 is controlled by the HSP90/R2TP chaperones

2017 ◽  
Vol 216 (6) ◽  
pp. 1579-1596 ◽  
Author(s):  
Anna Malinová ◽  
Zuzana Cvačková ◽  
Daniel Matějů ◽  
Zuzana Hořejší ◽  
Claire Abéza ◽  
...  
Keyword(s):  
Quantitative Proteomics ◽  
Mrna Splicing ◽  
Splicing Factor ◽  
Dependent Manner ◽  
Proteomics Data ◽  
Small Nuclear Ribonucleoprotein ◽  
Crucial Component ◽  
Potential Link ◽  
Nuclear Ribonucleoprotein ◽  
New Interactions

Splicing is catalyzed by the spliceosome, a complex of five major small nuclear ribonucleoprotein particles (snRNPs). The pre-mRNA splicing factor PRPF8 is a crucial component of the U5 snRNP, and together with EFTUD2 and SNRNP200, it forms a central module of the spliceosome. Using quantitative proteomics, we identified assembly intermediates containing PRPF8, EFTUD2, and SNRNP200 in association with the HSP90/R2TP complex, its ZNHIT2 cofactor, and additional proteins. HSP90 and R2TP bind unassembled U5 proteins in the cytoplasm, stabilize them, and promote the formation of the U5 snRNP. We further found that PRPF8 mutants causing Retinitis pigmentosa assemble less efficiently with the U5 snRNP and bind more strongly to R2TP, with one mutant retained in the cytoplasm in an R2TP-dependent manner. We propose that the HSP90/R2TP chaperone system promotes the assembly of a key module of U5 snRNP while assuring the quality control of PRPF8. The proteomics data further reveal new interactions between R2TP and the tuberous sclerosis complex (TSC), pointing to a potential link between growth signals and the assembly of key cellular machines.

scholarly journals The pre-mRNA-splicing factor SF3a66 functions as a microtubule-binding and -bundling protein

2004 ◽  
Vol 382 (1) ◽  
pp. 223-230 ◽  
Author(s):  
Kei TAKENAKA ◽  
Hiroyuki NAKAGAWA ◽  
Shigeaki MIYAMOTO ◽  
Hiroaki MIKI
Keyword(s):  
Rna Splicing ◽  
Ectopic Expression ◽  
Neuroblastoma Cells ◽  
High Molecular Mass ◽  
Mrna Splicing ◽  
Splicing Factor ◽  
Canonical Function ◽  
High Affinity ◽  
Small Nuclear Ribonucleoprotein ◽  
Nuclear Ribonucleoprotein

SF3a (splicing factor 3a) complex is an essential component of U2 snRNPs (small nuclear ribonucleoprotein particles), which are involved in pre-mRNA splicing. This complex consists of three subunits: SF3a60, SF3a66 and SF3a120. Here, we report a possible non-canonical function of a well-characterized RNA-splicing factor, SF3a66. Ectopic expression experiments using each SF3a subunit in N1E 115 neuroblastoma cells reveals that SF3a66 alone can induce neurite extension, suggesting that SF3a66 functions in the regulation of cell morphology. A screen for proteins that bind to SF3a66 clarifies that SF3a66 binds to β-tubulin, and also to microtubules, with high affinity, indicating that SF3a66 is a novel MAP (microtubule-associated protein). Electron microscopy experiments show that SF3a66 can bundle microtubules, and that bundling of microtubules is due to cross-bridging of microtubules by high-molecular-mass complexes of oligomerized SF3a66. These results indicate that SF3a66 is likely to be a novel MAP, and can function as a microtubule-bundling protein independently of RNA splicing.

Structure–function analysis of the U2 snRNP-associated splicing factor SF3a

2005 ◽  
Vol 33 (3) ◽  
pp. 439-442 ◽  
Author(s):  
A. Krämer ◽  
F. Ferfoglia ◽  
C.-J. Huang ◽  
F. Mulhaupt ◽  
D. Nesic ◽  
...  
Keyword(s):  
Structure Function ◽  
Function Analysis ◽  
Intracellular Localization ◽  
Splicing Factor ◽  
Branch Site ◽  
Small Nuclear Ribonucleoprotein ◽  
U2 Snrnp ◽  
Constitutive Splicing ◽  
Nuclear Ribonucleoprotein

Human splicing factor SF3a is a part of the 17 S U2 snRNP (small nuclear ribonucleoprotein), which interacts with the pre-mRNA branch site early during spliceosome formation. The SF3a subunits of 60, 66 and 120 kDa are all required for SF3a function in vitro. Depletion of individual subunits from HeLa cells by RNA interference results in a global inhibition of splicing, indicating that SF3a is a constitutive splicing factor. Structure–function analyses have defined domains necessary for interactions within the SF3a heterotrimer, association with the U2 snRNP and spliceosome assembly. Studies aimed at the identification of regions in SF3a60 and SF3a66, required for proper intracellular localization, have led to a model for the final steps in U2 snRNP biogenesis and the proposal that SF3a is incorporated into the U2 snRNP in Cajal bodies.

scholarly journals Chironomus tentans-Repressor Splicing Factor Represses SR Protein Function Locally on Pre-mRNA Exons and Is Displaced at Correct Splice Sites

2006 ◽  
Vol 17 (1) ◽  
pp. 32-42 ◽  
Author(s):  
Petra Björk ◽  
Ingela Wetterberg-Strandh ◽  
Göran Baurén ◽  
Lars Wieslander
Keyword(s):  
Protein Function ◽  
Splicing Factor ◽  
Chironomus Tentans ◽  
Splice Sites ◽  
Sr Protein ◽  
Small Nuclear Ribonucleoprotein ◽  
Nuclear Extracts ◽  
Interchromatin Granule ◽  
Nuclear Ribonucleoprotein

Chironomus tentans-repressor splicing factor (Ct-RSF) represses the activation of splicing by SR proteins in vitro. Ct-RSF colocalizes with the Ser-Arg-rich (SR) protein hrp45 in interchromatin granule clusters and coimmunoprecipitates with hrp45 in nuclear extracts. Ct-RSF and hrp45 can also interact directly in vitro. Ct-RSF and hrp45 are recruited together to transcribing genes and associate with growing pre-mRNAs. Ct-RSF and hrp45 colocalize at a large number of gene loci. Injection of anti-Ct-RSF antibodies into nuclei of living cells blocks association of both Ct-RSF and hrp45 with the growing pre-mRNA, whereas binding of U2 small nuclear ribonucleoprotein particle (snRNP) to the pre-mRNA is unaffected. On the intron-rich Balbiani ring (BR) 3 pre-mRNA, hrp45 as well as U1 and U2 snRNPs bind extensively, whereas relatively little Ct-RSF is present. In contrast, the BR1 and BR2 pre-mRNAs, dominated by exon sequences, bind relatively much Ct-RSF compared with hrp45 and snRNPs. Our data suggest that Ct-RSF represses SR protein function at exons and that the assembly of spliceosomes at authentic splice sites displaces Ct-RSF locally.

Sign in / Sign up

Export Citation Format

Share Document