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Alternative splicing during chondrogenesis: Modulation of fibronectin exon EIIIA splicing by SR proteins
Author(s) -
Kuo Bruce A.,
Uporova Tatiana M.,
Liang Hongyan,
Bennett Vickie D.,
Tuan Rocky S.,
Norton Pamela A.
Publication year - 2002
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.10188
Subject(s) - alternative splicing , exon , rna splicing , sr protein , microbiology and biotechnology , protein splicing , messenger rna , exonic splicing enhancer , minigene , biology , precursor mrna , polypyrimidine tract , chemistry , rna , gene , genetics
The alternative exon EIIIA of the fibronectin gene is included in mRNAs produced in undifferentiated mesenchymal cells but excluded from differentiated chondrocytes. As members of the SR protein family of splicing factors have been demonstrated to be involved in the alternative splicing of other mRNAs, the role of SR proteins in chondrogenesis‐associated EIIIA splicing was investigated. SR proteins interacted with chick exon EIIIA sequences that are required for exon inclusion in a gel mobility shift assay. Addition of SR proteins to in vitro splicing reactions increased the rate and extent of exon EIIIA inclusion. Co‐transfection studies employing cDNAs encoding individual SR proteins revealed that SRp20 decreased mRNA accumulation in HeLa cells, which make A+ mRNA, apparently by interfering with pre‐mRNA splicing. Co‐transfection studies also demonstrated that SRp40 increased exon EIIIA inclusion in chondrocytes, but not in HeLa cells, suggesting the importance of cellular context for SR protein activity. Immunoblot analysis did not reveal a relative depletion of SRp40 in chondrocytic cells. Possible mechanisms for regulation of EIIIA splicing in particular, and chondrogenesis associated splicing in general, are discussed. J. Cell. Biochem. 86: 45–55, 2002. © 2002 Wiley‐Liss, Inc.