Cooperative binding of TIA-1 and U1 snRNP in K-SAM exon splicing activation.
In 293 cells, splicing of the human fibroblast growth factor receptor-2 K-SAM alternative exon is inefficient, but can be made efficient by provoking TIA-1 binding to the U-rich IAS1 sequence downstream from the exon's 5' splice site. We show here that TIA-1 domains known to interact with U1 snRNP and to recruit it to 5' splice sites in vitro are required for TIA-1 activation of K-SAM exon splicing in vivo. We further show that tethering downstream from the K-SAM exon a fusion between the U1 snRNP component U1C and the bacteriophage MS2 coat protein provokes IAS1-dependent exon splicing, and present evidence that the fusion functions after its incorporation into U1 snRNP. Our in vivo data, taken together with previous in vitro results, show that K-SAM splicing activation involves cooperative binding of TIA-1 and U1 snRNP to the exon's 5' splice site region.
Gesnel
Marie-Claude
MC
INSERM, U601, Institut de Biologie-CHR, 9 quai Moncousu, 44093 Nantes Cedex 1, France.
Theoleyre
Sandrine
S
Del Gatto-Konczak
Fabienne
F
Breathnach
Richard
R
D017398:Alternative Splicing / Q000235:genetics*; D001665:Binding Sites; D002460:Cell Line; D005091:Exons / Q000235:genetics*; D006801:Humans; D007668:Kidney / Q000502:physiology*; D039102:Poly(A)-Binding Proteins / Q000235:genetics*; D011485:Protein Binding; D022821:RNA Splice Sites / Q000235:genetics; D051497:Receptor, Fibroblast Growth Factor, Type 2 / Q000235:genetics*; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000235:genetics*; D000074019:T-Cell Intracellular Antigen-1; D015533:Transcriptional Activation / Q000235:genetics*
D039102:Poly(A)-Binding Proteins; D022821:RNA Splice Sites; D017412:Ribonucleoprotein, U1 Small Nuclear; D000074019:T-Cell Intracellular Antigen-1; C071558:TIA1 protein, human; C496353:FGFR2 protein, human; D051497:Receptor, Fibroblast Growth Factor, Type 2