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Polypyrimidine tract sequences direct selection of alternative branch sites and influence protein binding.
Nucleic Acids Res. 1994 Sep 25; 22(19):3854-60.NA

Abstract

IVS1, an intron derived from the rat fibronectin gene, is spliced inefficiently in vitro, involving the use of three alternative branch sites. Mutation of one branch point site, BP3, so as to increase complementarity to U2 snRNA resulted in exclusive use of that site and improved splicing efficiency, indicating that the wild type BP3 site is one determinant of poor IVS1 splicing. Deletions within the polypyrimidine tract had a variable effect on splicing efficiency and altered the pattern of branch site usage. Selection of each branch site was influenced negatively by purine substitutions ca. 20 nucleotides downstream. It is proposed that all three IVS1 branch sites are pyrimidine tract-dependent. Pyrimidine tract deletions also influenced the crosslinking of PTB (the polypyrimidine tract-binding protein), hnRNP C, and splicing factor U2AF65. All three proteins bound preferentially to distinct regions within the polypyrimidine tract and thus are candidates for mediating pyrimidine tract-dependent branch site selection. The findings indicate the complexity of the IVS1 polypyrimidine tract and suggest a crucial role for this region in modulating branch site selection and IVS1 splicing.

Authors+Show Affiliations

Department of Medicine, Roger Williams Medical Center, Providence, RI 02908.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

7937104

Citation

Norton, P A.. "Polypyrimidine Tract Sequences Direct Selection of Alternative Branch Sites and Influence Protein Binding." Nucleic Acids Research, vol. 22, no. 19, 1994, pp. 3854-60.
Norton PA. Polypyrimidine tract sequences direct selection of alternative branch sites and influence protein binding. Nucleic Acids Res. 1994;22(19):3854-60.
Norton, P. A. (1994). Polypyrimidine tract sequences direct selection of alternative branch sites and influence protein binding. Nucleic Acids Research, 22(19), 3854-60.
Norton PA. Polypyrimidine Tract Sequences Direct Selection of Alternative Branch Sites and Influence Protein Binding. Nucleic Acids Res. 1994 Sep 25;22(19):3854-60. PubMed PMID: 7937104.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Polypyrimidine tract sequences direct selection of alternative branch sites and influence protein binding. A1 - Norton,P A, PY - 1994/9/25/pubmed PY - 1994/9/25/medline PY - 1994/9/25/entrez SP - 3854 EP - 60 JF - Nucleic acids research JO - Nucleic Acids Res VL - 22 IS - 19 N2 - IVS1, an intron derived from the rat fibronectin gene, is spliced inefficiently in vitro, involving the use of three alternative branch sites. Mutation of one branch point site, BP3, so as to increase complementarity to U2 snRNA resulted in exclusive use of that site and improved splicing efficiency, indicating that the wild type BP3 site is one determinant of poor IVS1 splicing. Deletions within the polypyrimidine tract had a variable effect on splicing efficiency and altered the pattern of branch site usage. Selection of each branch site was influenced negatively by purine substitutions ca. 20 nucleotides downstream. It is proposed that all three IVS1 branch sites are pyrimidine tract-dependent. Pyrimidine tract deletions also influenced the crosslinking of PTB (the polypyrimidine tract-binding protein), hnRNP C, and splicing factor U2AF65. All three proteins bound preferentially to distinct regions within the polypyrimidine tract and thus are candidates for mediating pyrimidine tract-dependent branch site selection. The findings indicate the complexity of the IVS1 polypyrimidine tract and suggest a crucial role for this region in modulating branch site selection and IVS1 splicing. SN - 0305-1048 UR - https://www.unboundmedicine.com/medline/citation/7937104/Polypyrimidine_tract_sequences_direct_selection_of_alternative_branch_sites_and_influence_protein_binding_ L2 - https://academic.oup.com/nar/article-lookup/doi/10.1093/nar/22.19.3854 DB - PRIME DP - Unbound Medicine ER -