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Interaction of hnRNP A1 with snRNPs and ... t steps of spliceosome assembly
Interaction of hnRNP A1 with snRNPs and pre-mRNAs evidence for a possible role of A1 RNA annealing activity in the first steps of spliceosome assembly
5161
The in vitro interaction of recombinant hnRNP A1 with purified snRNPs and with pre-mRNAs was investigated. We show that protein A1 can stably bind U2 and U4 snRNP but not U1. Oligo-RNAse H cleavage of U2 nucleotides involved in base pairing with the branch site, totally eliminates the A1-U2 interaction. RNase T1 protection and immunoprecipitation experiments demonstrate that recombinant protein A1 specifically binds the 3'-end regions of both beta-globin and Ad-2 introns. However, while on the beta-globin intron only binding to the polypyrimidine tract was observed, on the Ad-2 intron a 32 nt fragment encompassing the branch point and the AG splice-site dinucleotide was bound and protected. Such protection was drastically reduced in the presence of U2 snRNP. Altogether these results indicate that protein A1 can establish a different pattern of association with different pre-mRNAs and support the hypothesis that this protein could play a role in the annealing of U2 to the branch site and hence in the early events of pre-splicing complex assembly.
Buvoli M, Cobianchi F, Riva S
Nucleic acids research
1992-10-11 00:00
20
19
5017-25
Adenoviruses, Human,Base Sequence,Globins,Heterogeneous-Nuclear Ribonucleoprotein Group A-B,Heterogeneous-Nuclear Ribonucleoproteins,Humans,Introns,Molecular Sequence Data,Oligodeoxyribonucleotides,Protein Biosynthesis,RNA Precursors,RNA Splicing,RNA, Heterogeneous Nuclear,RNA, Small Nuclear,Recombinant Proteins,Ribonuclease H, Calf Thymus,Ribonuclease T1,Ribonucleoproteins,Ribonucleoproteins, Small Nuclear,Spliceosomes,Heterogeneous-Nuclear Ribonucleoprotein Group A-B,Heterogeneous-Nuclear Ribonucleoproteins,Oligodeoxyribonucleotides,RNA Precursors,RNA, Heterogeneous Nuclear,RNA, Small Nuclear,Recombinant Proteins,Ribonucleoproteins,Ribonucleoproteins, Small Nuclear,hnRNP A1,Globins,Ribonuclease H, Calf Thymus,Ribonuclease T1
Istituto di Genetica Biochimica ed Evoluzionistica, CNR, Pavia, Italy.
Nucleic Acids Res.
0305-1048
0
False
1329035
