Sumner C, Shinohara T, Durham L, Traub R, Major E O, Amemiya K
Laboratory of Molecular Medicine and Neuroscience, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA.
J Neurovirol. 1996 Apr;2(2):87-100. doi: 10.3109/13550289609146542.
Nuclear factor-1 (NF-1) is a multifunctional protein that participates in both transcription and replication. NF-1 proteins exist as a family of proteins that share some common structural and functional features but also demonstrate organ and cell type specific expression. Based upon these characteristics, the family of NF-1 proteins is divided into four classes, A, B, C and D. Several NF-1 binding sites have been identified in the regulatory sequences of the human polyomavirus, JCV, which multiplies most efficiently in glial cells derived from human fetal brain. Nuclear proteins from these cultures bind specifically to these NF-1 sites. It is not known, however, which member(s) of the NF-1 family is expressed in cells susceptible to JCV infection. We have examined glial cells as well as HeLa cells, which are not permissive to JCV, for NF-1 expression. By RT-PCR analysis, all four classes of NF-1 are expressed in human fetal glial cells and HeLa cells. However, by Northern analysis the expression of class D gene is much higher in the glial cells than HeLa cells. Expression of the class C gene, first identified in HeLa cells as NF-1/CTF1, is barely detectable in glial cells but highly expressed in HeLa cells. The screening of cDNA libraries from two early human brain tissues resulted in the identification of a number of clones which appear to be related and belong to a single class of the NF-1 family, class D. Nucleotide sequence of one clone, designated NF-1/AT1, confirms this. The NF-1/AT1 protein was overexpressed in E coli and found to bind specifically to an NF-1 probe by gel shift analysis. Southern analysis of human fetal glial cells indicates that the NF-1/AT1 gene, class D, is derived from a different gene than NF-1/CTF1. These results suggest the possibility that genes or viruses, like JCV, which use NF-1 for their expression in human brain derived cells may preferentially use the NF-1 class D protein.
核因子-1（NF-1）是一种多功能蛋白，参与转录和复制过程。NF-1蛋白以蛋白家族形式存在，它们具有一些共同的结构和功能特征，但也表现出器官和细胞类型特异性表达。基于这些特性，NF-1蛋白家族分为A、B、C和D四类。在人类多瘤病毒JCV的调控序列中已鉴定出多个NF-1结合位点，JCV在源自人类胎儿脑的神经胶质细胞中增殖效率最高。来自这些培养物的核蛋白特异性结合这些NF-1位点。然而，尚不清楚NF-1家族的哪些成员在易受JCV感染的细胞中表达。我们检测了神经胶质细胞以及对JCV不敏感的HeLa细胞中的NF-1表达。通过RT-PCR分析，所有四类NF-1在人类胎儿神经胶质细胞和HeLa细胞中均有表达。然而，通过Northern分析，D类基因在神经胶质细胞中的表达远高于HeLa细胞。C类基因最初在HeLa细胞中被鉴定为NF-1/CTF1，在神经胶质细胞中几乎检测不到，但在HeLa细胞中高度表达。对两个早期人类脑组织的cDNA文库进行筛选，鉴定出了一些似乎相关且属于NF-1家族单一类别的克隆，即D类。一个名为NF-1/AT1的克隆的核苷酸序列证实了这一点。NF-1/AT1蛋白在大肠杆菌中过表达，并通过凝胶迁移分析发现其特异性结合NF-1探针。对人类胎儿神经胶质细胞的Southern分析表明，D类NF-1/AT1基因与NF-1/CTF1基因不同。这些结果表明，像JCV这样在源自人类脑的细胞中利用NF-1进行表达的基因或病毒可能优先使用D类NF-1蛋白。
