Identification Of A Complex Involved In Werner Syndrome

沃纳综合征（WS）是一种罕见的人类遗传性疾病，具有许多早衰的特征。它已被许多研究人员认为是人类衰老研究的一个有用模型。WS中涉及的基因最近被克隆并命名为WRN。它编码与解旋酶的RecQ家族同源的蛋白质。实际上，使用杆状病毒表达系统产生的重组WRN蛋白含有DNA解旋酶活性以及核酸外切酶活性。有趣的是，对不同WS患者的分析表明，一些WRN突变可能会损害WRN与其他蛋白质之间的相互作用。这提出了WRN在体内多亚基蛋白复合物中发挥功能的可能性。我们已经成功地纯化了一个这样的复合物，并通过微测序鉴定了其所有亚基。我们发现该复合物含有DNA-PKcs、Ku 86和Ku 70蛋白。所有这些WRNp伙伴先前已被证明参与DNA损伤的修复和导致细胞周期停滞和细胞死亡的信号通路。我们的结果与其他研究小组的几篇论文一致，这些论文也发现了WRNp与这些蛋白质之间的相互作用。最近，我们使用不同的WRNp抗体，分离了不同形式的WRN复合物，这种新的复合物不仅含有DNA-PKcs，而且还含有几种新的蛋白质。其中之一似乎是核纤层蛋白的相互作用蛋白。核纤层蛋白的一种形式，核纤层蛋白-A，已被发现在Hutchinson-Gilford早衰症中有缺陷。我们推测，这种相互作用的蛋白质可能在这两种疾病的过早衰老中发挥共同作用，目前正在研究这种联系。

The Werner Syndrome (WS) is a rare human genetic disease with many features of premature aging. It has been considered by many researchers as a useful model for human aging studies. The gene involved in WS has recently been cloned and was named WRN. It encodes a protein homologous to RecQ family of helicases. Indeed, the recombinant WRN protein produced using a baculovirus expression system contains a DNA helicase activity as well as an exonuclease activity. Interestingly, analysis of different WS patients suggests that some WRN mutations may impair the interactions between WRN and other proteins. This raised the possibility that WRN functions within a multisubunit protein complex in vivo. We have successfully purified one such complex and identified all its subunits by microsequencing. We found that this complex contains DNA-PKcs, Ku86, and Ku70 proteins. All these WRNp partners have previously been shown to participate in repair of DNA damage and in signaling pathways leading to cell cycle arrest and cell death. Our results are consistent with several publications from other groups which also found the interaction between WRNp and these proteins. Recently, we have used a different WRNp antibody and isolated a different form of the WRN complex, This new complex contains not only the DNA-PKcs, but also several novel proteins. One of them appears to be an interacting protein for lamin. One form of lamin, lamin-A, has been found to be defective in Hutchinson-Gilford progeria. We are speculating that this interacting protein may play a common role in premature aging from both diseases, and are currently investigating this connection.