The carboxyl-terminal region common to lamins A and C contains a DNA binding domain
The carboxyl-terminal region common to lamins A and C contains a DNA binding domain
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DOI：
10.1021/bi020704g
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发表时间：
2003-05-06
期刊：
影响因子：
2.9
通讯作者：
Duband-Goulet, I
中科院分区：
文献类型：
--
作者：
Stierlé, VN;Couprie, JL;Duband-Goulet, I
核纤层蛋白 A 和 C 是中间丝蛋白，它们聚合到细胞核中形成核纤层网络。核纤层与内核膜相邻，其功能是将染色质束缚到核膜上并维持核形状。我们最近表征了一个球状结构域，该结构域采用核纤层蛋白 A 和 C 共有的羧基末端尾部中的免疫球蛋白折叠。使用电泳迁移率变动测定 (EMSA)，我们表明含有该结构域的肽在体外通过二硫键二聚化后与 DNA 相互作用，但不与核心颗粒或双核小体相互作用。共价二聚体以微摩尔亲和力结合 30-40 bp DNA 片段，无序列特异性。使用核磁共振 (NMR) 和 EMSA，我们观察到两个肽区域参与 DNA 结合：包含核定位信号的非结构化氨基末端部分和以免疫球蛋白样结构域表面的氨基酸 R482 为中心的大带正电区域。突变 R482Q 和 -W 导致 Dunnigan 型部分脂肪营养不良，降低了肽与 DNA 的亲和力。我们得出结论，核纤层蛋白 A 和 C 的羧基末端结合 DNA，并表明核纤层蛋白 -DNA 相互作用的改变可能在一些核纤层蛋白相关疾病的病理生理学中发挥作用。
Lamins A and C are intermediate filament proteins which polymerize into the nucleus to form the nuclear lamina network. The lamina is apposed to the inner nuclear membrane and functions in tethering chromatin to the nuclear envelope and in maintaining nuclear shape. We have recently characterized a globular domain that adopts an immunoglobulin fold in the carboxyl-terminal tail common to lamins A and C. Using an electrophoretic mobility shift assay (EMSA), we show that a peptide containing this domain interacts in vitro with DNA after dimerization through a disulfide bond, but does not interact with the core particle or the dinucleosome. The covalent dimer binds a 30-40 bp DNA fragment with a micromolar affinity and no sequence specificity. Using nuclear magnetic resonance (NMR) and an EMSA, we observed that two peptide regions participate in the DNA binding: the unstructured amino-terminal part containing the nuclear localization signal and a large positively charged region centered around amino acid R482 at the surface of the immunoglobulin-like domain. Mutations R482Q and -W, which are responsible for Dunnigan-type partial lipodystrophy, lower the affinity of the peptide for DNA. We conclude that the carboxyl-terminal end of lamins A and C binds DNA and suggest that alterations in lamin-DNA interactions may play a role in the pathophysiology of some lamin-linked diseases.