Ting J, Lee A S
Department of Biochemistry, University of Southern California School of Medicine, Los Angeles 90033.
DNA. 1988 May;7(4):275-86. doi: 10.1089/dna.1988.7.275.
The isolation and characterization of a human functional GRP78 gene and a processed pseudogene are described. We present the complete primary structure of the human GRP78 gene, which spans over 5 kb and consists of eight exons. Sequence comparisons reveal that the GRP78 gene shares unusual homology among the human, rat, and hamster in the protein-coding and 3' untranslated regions. In addition, short domains highly conserved with HSP70 isolated from human, Drosophila, Xenopus, yeast, and E. coli DNA are identified within the hydrophobic regions of GRP78. The intronless pseudogene resembles that of a processed gene. It is flanked by a short direct repeat and is embedded within an AT-rich genomic region. The highly active promoter from the functional human GRP78 gene contains a TATA box, five CCAAT sequences, and two potential binding sites for the transcriptional factor Sp1. It consists of a distal domain that enhances basal level expression and a proximal domain essential for responses to calcium ionophore and for a temperature-sensitive mutation which induce the GRP78 gene. Both domains are highly conserved between the rat and the human GRP78 promoters.
本文描述了人类功能性GRP78基因和一个加工假基因的分离与特性。我们展示了人类GRP78基因完整的一级结构，该基因跨度超过5 kb，由八个外显子组成。序列比较显示，GRP78基因在人类、大鼠和仓鼠的蛋白质编码区和3'非翻译区具有异常的同源性。此外，在GRP78的疏水区域内鉴定出与从人类、果蝇、非洲爪蟾、酵母和大肠杆菌DNA中分离出的HSP70高度保守的短结构域。无内含子假基因类似于加工基因。它两侧有短的同向重复序列，并嵌入富含AT的基因组区域。功能性人类GRP78基因的高活性启动子包含一个TATA盒、五个CCAAT序列以及转录因子Sp1的两个潜在结合位点。它由一个增强基础水平表达的远端结构域和一个对钙离子载体反应以及对诱导GRP78基因的温度敏感突变至关重要的近端结构域组成。这两个结构域在大鼠和人类GRP78启动子之间高度保守。
