Chen H R, Tsao T Y, Chen C H, Tsai W Y, Her L S, Hsu M M, Cheng S C
Institute of Microbiology and Immunology, National Yang-Ming University, Shih-Pai, Taiwan 112.
Proc Natl Acad Sci U S A. 1999 May 11;96(10):5406-11. doi: 10.1073/pnas.96.10.5406.
The SNT309 gene was identified via a mutation that causes lethality of cells in combination with a prp19 mutation. We showed previously that Snt309p is a component of the Prp19p-associated complex and that Snt309p, like Prp19p, is associated with the spliceosome immediately after or concomitantly with dissociation of U4 from the spliceosome. We show here that extracts prepared from the SNT309-deleted strain (DeltaSNT309) were defective in splicing but could be complemented by addition of the purified Prp19p-associated complex. Isolation of the Prp19p-associated complex from DeltaSNT309 extracts indicated that the complex was destabilized in the absence of Snt309p and dissociated on affinity chromatography, suggesting a role of Snt309p in stabilization of the Prp19p-associated complex. Addition of the affinity-purified Prp19p-Snt309p binary complex to DeltaSNT309 extracts could reconstitute the Prp19p-associated complex. Genetic analysis further suggests that Snt309p plays a role in modulating interactions of Prp19p with other associated components to facilitate formation of the Prp19p-associated complex. A model for how Snt309p modulates such interactions is proposed.
SNT309基因是通过一种与prp19突变结合会导致细胞致死的突变而被鉴定出来的。我们之前表明，Snt309p是与Prp19p相关复合物的一个组分，并且Snt309p与Prp19p一样，在U4从剪接体解离后立即或同时与剪接体相关联。我们在此表明，从缺失SNT309的菌株（DeltaSNT309）制备的提取物在剪接方面存在缺陷，但可以通过添加纯化的与Prp19p相关的复合物来互补。从DeltaSNT309提取物中分离与Prp19p相关的复合物表明，在没有Snt309p的情况下该复合物不稳定，并且在亲和层析上解离，这表明Snt309p在稳定与Prp19p相关的复合物中起作用。将亲和纯化的Prp19p - Snt309p二元复合物添加到DeltaSNT309提取物中可以重建与Prp19p相关的复合物。遗传分析进一步表明，Snt309p在调节Prp19p与其他相关组分的相互作用以促进与Prp19p相关的复合物形成中起作用。本文提出了一个关于Snt309p如何调节这种相互作用的模型。
