SR proteins are sufficient for exon bridging across an intron.
We have developed a defined system to characterize the role of SR proteins and exonic enhancers in directly promoting splice-site interactions across an intron. Using RNA affinity chromatography, we find that SR proteins alone are sufficient to promote the specific association of the enhancer-containing exon 5 with the adjoining exon 6 from avian cardiac troponin-T. Direct visualization of this exon/exon association by electron spectroscopic imaging shows it to be highly specific. Furthermore, using in vivo characterized mutants of exon 5, we also show that this exon/exon association depends on the splicing enhancer within exon 5. These results suggest a model by which SR proteins may function through exonic enhancers to directly promote exon bridging.
Stark
J M
JM
Division of Basic Sciences and Molecular and Cellular Biology Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98104, USA.
Bazett-Jones
D P
DP
Herfort
M
M
Roth
M B
MB
D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002417:Cattle; D002846:Chromatography, Affinity; D004247:DNA / Q000378:metabolism / Q000648:ultrastructure; D004742:Enhancer Elements, Genetic; D005091:Exons; D006367:HeLa Cells; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D000068103:Serine-Arginine Splicing Factors; D013950:Thymus Gland / Q000378:metabolism
D009687:Nuclear Proteins; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D000068103:Serine-Arginine Splicing Factors; D004247:DNA