Ismaïli N, Pérez-Morga D, Walsh P, Mayeda A, Pays A, Tebabi P, Krainer A R, Pays E
Department of Molecular Biology, Free University of Brussels, Rhode St Genèse, Belgium.
Mol Biochem Parasitol. 1999 Jul 30;102(1):103-15. doi: 10.1016/s0166-6851(99)00091-2.
The protozoan parasite Trypanosoma brucei relies on trans-splicing to process its mRNAs. A novel nuclear serine/arginine (SR)-rich trypanosomal protein (TSR1) was characterized which contains two RNA recognition motifs. The TSR1 protein appears to be homologous to RNA-binding SR proteins of the cis-splicing machinery from higher eukaryotes. Moreover, in the yeast two-hybrid system, TSR1 is able to interact with the human splicing factors involved in the recognition of the 3' splicing site (U2AF35/U2AF65). In both procyclic and bloodstream forms of T. brucei, TSR1 was found to localize in the nucleus. In the bloodstream stage TSR1 showed the speckles pattern characteristic of SR proteins involved in cis-splicing. Moreover, TSR1 was able to specifically bind the spliced leader (SL) RNA involved in trans-splicing in trypanosomes by the yeast three-hybrid system. These and other observations suggest that TSR1 may be involved in trans-splicing in T. brucei.
原生动物寄生虫布氏锥虫依靠反式剪接来加工其信使核糖核酸（mRNA）。一种新的富含核丝氨酸/精氨酸（SR）的锥虫蛋白（TSR1）被鉴定出来，它含有两个RNA识别基序。TSR1蛋白似乎与高等真核生物顺式剪接机制中的RNA结合SR蛋白同源。此外，在酵母双杂交系统中，TSR1能够与参与识别3'剪接位点的人类剪接因子（U2AF35/U2AF65）相互作用。在布氏锥虫的前循环型和血流型中，均发现TSR1定位于细胞核。在血流阶段，TSR1呈现出参与顺式剪接的SR蛋白特有的斑点模式。此外，通过酵母三杂交系统，TSR1能够特异性结合锥虫反式剪接中涉及的剪接前导（SL）RNA。这些以及其他观察结果表明，TSR1可能参与布氏锥虫的反式剪接。
