Gesnel Marie-Claude, Theoleyre Sandrine, Del Gatto-Konczak Fabienne, Breathnach Richard
INSERM, U601, Institut de Biologie-CHR, 9 quai Moncousu, 44093 Nantes Cedex 1, France.
Biochem Biophys Res Commun. 2007 Jul 13;358(4):1065-70. doi: 10.1016/j.bbrc.2007.05.050. Epub 2007 May 15.
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.
在293细胞中，人成纤维细胞生长因子受体-2 K-SAM可变外显子的剪接效率低下，但通过促使TIA-1与该外显子5'剪接位点下游富含U的IAS1序列结合，可使其剪接效率提高。我们在此表明，已知在体外与U1 snRNP相互作用并将其招募至5'剪接位点的TIA-1结构域，是TIA-1在体内激活K-SAM外显子剪接所必需的。我们进一步表明，将U1 snRNP组分U1C与噬菌体MS2外壳蛋白的融合体拴系在K-SAM外显子下游，可引发依赖IAS1的外显子剪接，并提供证据表明该融合体在掺入U1 snRNP后发挥作用。我们的体内数据与先前的体外结果相结合，表明K-SAM剪接激活涉及TIA-1和U1 snRNP与外显子5'剪接位点区域的协同结合。
