Regulation of SRp20 exon 4 splicing.
SR proteins are essential splicing factors involved in the use of both constitutive and alternative exons. We previously showed that the SR proteins SRp20 and ASF/SF2 have antagonistic activities on SRp20 pre-mRNA splicing. SRp20 activates exon 4 recognition in its pre-mRNA, whereas ASF/SF2 inhibits this recognition. In experiments aimed at testing the specificity of SRp20 and ASF/SF2 for exon 4 splicing regulation, we show here that this specificity lies in the RNA binding domains of SRp20 and ASF/SF2 and not in the RS domains. Surprisingly, a deletion of 14 amino acids at the end of ASF/SF2-RBD2 converts ASF/SF2 from an inhibitor to an activator of exon 4 splicing. We found that ASF3 also inhibits exon 4 recognition, thus acting similarly to ASF/SF2, while SC35 activates a cryptic 5' splice site downstream of exon 3 and, in doing so, represses exon 4 use. In contrast, Tra2 and the SR proteins 9G8 and SRp40 do not appear to affect exon 4 splicing.
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Max Planck Institute for Immunobiology, Stuebeweg 51, D-79108, i. Br, Freiburg, Germany. nielsen@immunbio.mpg.de
Nielsen
P J
PJ
D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D029721:Drosophila Proteins; D005091:Exons / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012322:RNA Precursors / Q000235:genetics* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000378:metabolism; D017384:Sequence Deletion / Q000235:genetics; D000068103:Serine-Arginine Splicing Factors; D013379:Substrate Specificity; D014162:Transfection; D014407:Tumor Cells, Cultured
D029721:Drosophila Proteins; D009687:Nuclear Proteins; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D012261:Ribonucleoproteins; C499372:SRSF2 protein, mouse; C491388:SRSF3 protein, human; C106161:Srsf3 protein, mouse; C066174:tra2 protein, Drosophila; D000068103:Serine-Arginine Splicing Factors