Alternative splicing of tropomyosin pre-mRNAs in vitro and in vivo

Helfman, D. M., Ricci, W. M., Finn, L. A. (December 1988) Alternative splicing of tropomyosin pre-mRNAs in vitro and in vivo. Genes Dev, 2 (12A). pp. 1627-38. ISSN 0890-9369

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Abstract

A single rat gene encodes both fibroblast TM-1 and skeletal muscle beta-tropomyosin by an alternative RNA-processing mechanism. The gene contains 11 exons: Exons 1-5 and exons 8 and 9 are constitutive exons common to all mRNAs expressed from this gene; exons 6 and 11 are used in fibroblasts as well as smooth muscle; exons 7 and 10 are used exclusively in skeletal muscle. We have studied the internal alternative RNA splice choice (exons 6 and 7) of the rat tropomyosin 1 gene in vitro, using nuclear extracts obtained from HeLa cells. Use of alternative splice sites in vitro is dependent on the ionic conditions of the assay, and correct splicing occurs only under well-defined salt conditions. Splicing of exon 5 to exon 6 (fibroblast-type splice) and exon 5 to exon 7 (skeletal muscle-type splice) was dependent on precursors in which exon 6 or 7 was first joined to exon 8. The same patterns of alternatively spliced RNAs were formed when similar templates were introduced in HeLa cells by transfection. Thus, there appears to be an ordered pathway of splicing in which the internal alternatively spliced exons must first be joined to the downstream constitutive exon before they can be spliced to the upstream constitutive exon. The data are consistent with a model in which the critical event in alternative splicing occurs during the joining of exon 6 to exon 8 (fibroblast-type splice) or exon 7 to exon 8 (skeletal muscle-type splice).

Item Type: Paper
Uncontrolled Keywords: Animals Cell Extracts Exons Humans Introns Magnesium/pharmacology Magnesium Chloride Models, Genetic Plasmids Potassium Chloride/pharmacology RNA Precursors/genetics/*metabolism *RNA Splicing RNA, Messenger/*biosynthesis/genetics Rats Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. Transfection Tropomyosin/*biosynthesis/genetics
Subjects: organism description > animal > mammal > rodent > rat
organism description > animal > mammal > rodent > rat
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > splicing factor
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > tropomyosin
CSHL Authors:
Communities: CSHL labs
Depositing User: Gail Sherman
Date: December 1988
Date Deposited: 29 Sep 2017 14:52
Last Modified: 03 Nov 2017 20:59
Related URLs:
URI: https://repository.cshl.edu/id/eprint/35162

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