Tufts School of Medicine and the Sackler Graduate School of Biomedical Sciences, Boston, MA 02111, USA.
FEBS Lett. 2012 Apr 24;586(8):1173-8. doi: 10.1016/j.febslet.2012.03.036. Epub 2012 Mar 24.
Addition of poly(A) to the 3' ends of cleaved pre-mRNA is essential for mRNA maturation and is catalyzed by Pap1 in yeast. We have previously shown that a non-viable Pap1 mutant lacking the first 18 amino acids is fully active for polyadenylation of oligoA, but defective for pre-mRNA polyadenylation, suggesting that interactions at the N-terminus are important for enzyme function in the processing complex. We have now identified proteins that interact specifically with this region. Cft1 and Pta1 are subunits of the cleavage/polyadenylation factor, in which Pap1 resides, and Nab6 and Sub1 are nucleic-acid binding proteins with known links to 3' end processing. Our results suggest a novel mechanism for controlling Pap1 activity, and possible models invoking these newly-discovered interactions are discussed.
在酵母中，断裂前 mRNA 的 3' 端添加 poly(A) 对于 mRNA 成熟是必不可少的，该过程由 Pap1 催化。我们之前已经表明，缺乏前 18 个氨基酸的非活性 Pap1 突变体完全能够对寡聚 A 进行多聚腺苷酸化，但对于前 mRNA 多聚腺苷酸化却是有缺陷的，这表明 N 端的相互作用对于酶在加工复合物中的功能很重要。我们现在已经鉴定出与该区域特异性相互作用的蛋白质。Cft1 和 Pta1 是切割/多聚腺苷酸化因子的亚基，Pap1 就位于其中，而 Nab6 和 Sub1 是具有已知与 3' 端加工相关的核酸结合蛋白。我们的结果表明了一种控制 Pap1 活性的新机制，并讨论了可能涉及这些新发现的相互作用的模型。
