Proteomic analysis identifies a new complex required for nuclear pre-mRNA retention and splicing
Proteomic analysis identifies a new complex required for nuclear pre-mRNA retention and splicing
复制标题
DOI：
10.1038/sj.emboj.7600482
复制
发表时间：
2004-12-08
期刊：
影响因子：
11.4
通讯作者：
Séraphin, B
中科院分区：
文献类型：
--
作者：
Dziembowski, A;Ventura, AP;Séraphin, B
利用蛋白质组学串联亲和纯化（TAP）方法，我们纯化了酵母U2 snRNP相关剪接因子SF 3a和SF 3b。虽然SF 3a纯化仅显示预期的Prp 9 p、Prp 11 p和Prp 21 p亚基，但发现酵母SF 3b仅包含六个亚基，包括先前已知的组分（Rse 1 p、Hsh 155 p、Cus 1 p、Hsh 49 p）、最近鉴定的Rds 3 p因子和由酵母基因组中的未预测的分裂ORF编码的新的小必需蛋白（Ysf 3 p）。令人惊讶的是，在酵母复合物中没有发现Snu 17 p，即第七个人SF 3b亚基p14的酵母直向同源物。TAP纯化表明Snu 17 p与Bud 13 p和一个新鉴定的因子Pml 1 p/Ylr 016 c形成一种新的三聚体复合物。亚单位的这种复杂的生存能力不是必不可少的。然而，它们是体外和体内有效剪接所必需的。此外，该复合物的失活导致前mRNA从细胞核泄漏。相应的复合物被命名为前mRNA保留和剪接（RES）。RES亚基同源物在许多真核生物中的存在表明其功能在进化上是保守的。
Using the proteomic tandem affinity purification (TAP) method, we have purified the Saccharomyces cerevisie U2 snRNP-associated splicing factors SF3a and SF3b. While SF3a purification revealed only the expected subunits Prp9p, Prp11p and Prp21p, yeast SF3b was found to contain only six subunits, including previously known components (Rse1p, Hsh155p, Cus1p, Hsh49p), the recently identified Rds3p factor and a new small essential protein (Ysf3p) encoded by an unpredicted split ORF in the yeast genome. Surprisingly, Snu17p, the proposed yeast orthologue of the seventh human SF3b subunit, p14, was not found in the yeast complex. TAP purification revealed that Snu17p, together with Bud13p and a newly identified factor, Pml1p/Ylr016c, form a novel trimeric complex. Subunits of this complex were not essential for viability. However, they are required for efficient splicing in vitro and in vivo. Furthermore, inactivation of this complex causes pre-mRNA leakage from the nucleus. The corresponding complex was named pre-mRNA REtention and Splicing (RES). The presence of RES subunit homologues in numerous eukaryotes suggests that its function is evolutionarily conserved.