Elkind N B, Goldfinger N, Rotter V
Department of Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
Oncogene. 1995 Sep 7;11(5):841-51.
Nuclear Localization Signals (NLS) have been found to mediate the import of proteins into the nucleus. Proteins interacting directly with NLS control the subcellular localization of nucleophilic proteins. The p53 protein is spatially regulated throughout the cell cycle and this regulation has been shown to be dependent on the presence of its NLS sequences. We identified three novel cDNA clones that were isolated from an expression library because they encode polypeptides that bind a synthetic peptide containing the major NLS of p53 (NLS I). These clones were found to share a common domain encoded by p(CA)n repeats; a simple sequence length polymorphism (SSLP). THis is the first report where p(CA)n repeats were found to encode protein. One cDNA clone encodes a full length, 16 kDa protein, designated spot-1, that is represented in cells predominantly as oligomers. spot-1 interacts with the NLS I of p53 through its p(CA)n repeat. Cell fractionation and immunofluorescence analysis demonstrated that spot-1 is a nuclear protein which, in fibroblasts, co-localizes with p53.
核定位信号（NLS）已被发现可介导蛋白质进入细胞核。直接与NLS相互作用的蛋白质控制亲核蛋白的亚细胞定位。p53蛋白在整个细胞周期中受到空间调控，并且这种调控已被证明依赖于其NLS序列的存在。我们鉴定出了三个新的cDNA克隆，它们是从一个表达文库中分离出来的，因为它们编码与包含p53主要NLS（NLS I）的合成肽结合的多肽。发现这些克隆共享一个由p(CA)n重复序列编码的共同结构域；一种简单序列长度多态性（SSLP）。这是首次报道p(CA)n重复序列编码蛋白质。一个cDNA克隆编码一种全长16 kDa的蛋白质，命名为spot-1，它在细胞中主要以寡聚体形式存在。spot-1通过其p(CA)n重复序列与p53的NLS I相互作用。细胞分级分离和免疫荧光分析表明，spot-1是一种核蛋白，在成纤维细胞中与p53共定位。
