Distinct activities of the DExD/H-box splicing factor hUAP56 facilitate stepwise assembly of the spliceosome
Document Type
Journal ArticlePublication Date
2008-07-03Keywords
Adenosine TriphosphateDEAD-box RNA Helicases
Hela Cells
Humans
Hydrolysis
Mutation
Nuclear Proteins
Protein Binding
RNA Precursors
RNA Splicing
RNA, Double-Stranded
RNA, Small Nuclear
Ribonucleoprotein, U4-U6 Small Nuclear
Ribonucleoproteins
Spliceosomes
Genetics and Genomics
Metadata
Show full item recordAbstract
The essential splicing factor human UAP56 (hUAP56) is a DExD/H-box protein known to promote prespliceosome assembly. Here, using a series of hUAP56 mutants that are defective for ATP-binding, ATP hydrolysis, or dsRNA unwindase/helicase activity, we assess the relative contributions of these biochemical functions to pre-mRNA splicing. We show that prespliceosome assembly requires hUAP56's ATP-binding and ATPase activities, which, unexpectedly, are required for hUAP56 to interact with U2AF(65) and be recruited into splicing complexes. Surprisingly, we find that hUAP56 is also required for mature spliceosome assembly, which requires, in addition to the ATP-binding and ATPase activities, hUAP56's dsRNA unwindase/helicase activity. We demonstrate that hUAP56 directly contacts U4 and U6 snRNAs and can promote unwinding of the U4/U6 duplex, and that both these activities are dependent on U2AF(65). Our results indicate that hUAP56 first interacts with U2AF(65) in an ATP-dependent manner, and subsequently with U4/U6 snRNAs to facilitate stepwise assembly of the spliceosome.Source
Genes Dev. 2008 Jul 1;22(13):1796-803. Link to article on publisher's siteDOI
10.1101/gad.1657308Permanent Link to this Item
http://hdl.handle.net/20.500.14038/44115PubMed ID
18593880Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1101/gad.1657308