Scarr R B, Smith M R, Beddall M, Sharp P A
Center for Cancer Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Mol Cell Biol. 2000 May;20(10):3568-75. doi: 10.1128/MCB.20.10.3568-3575.2000.
Host cell factor 1 (HCF-1; also called C1) is a 230-kDa protein which is cleaved posttranslationally into separate but associated N- and C-terminal polypeptides. These polypeptides are components of the C1 complex, along with Oct-1 and the viral protein VP16. The C1 complex is formed when herpes simplex virus (HSV) infects a cell and is responsible for transcription of the HSV immediate-early genes. A temperature-sensitive mutation in the N-terminal kelch domain of HCF-1 reversibly arrests cells in a G(0)-like state when grown at the nonpermissive temperature, and the same domain interacts with VP16 in the formation of the C1 complex. The form of HCF-1 in primary G(0) cells was investigated by using peripheral blood mononucleocytes and serum-arrested human primary fibroblasts. A novel 50-kDa N-terminal fragment of HCF-1 encompassing the kelch domain was identified in the cytoplasm of these cells. This fragment arises by proteolysis of the full-length HCF-1 protein and is able to associate with VP16.
宿主细胞因子1（HCF-1；也称为C1）是一种230 kDa的蛋白质，其在翻译后被切割成单独但相关的N端和C端多肽。这些多肽与Oct-1和病毒蛋白VP16一起是C1复合物的组成成分。当单纯疱疹病毒（HSV）感染细胞时形成C1复合物，其负责HSV立即早期基因的转录。HCF-1的N端kelch结构域中的温度敏感突变在非允许温度下生长时会使细胞可逆地停滞在类似G(0)的状态，并且相同的结构域在C1复合物形成过程中与VP16相互作用。通过使用外周血单核细胞和血清停滞的人原代成纤维细胞研究了原代G(0)细胞中HCF-1的形式。在这些细胞的细胞质中鉴定出一种包含kelch结构域的新型50 kDa HCF-1 N端片段。该片段由全长HCF-1蛋白的蛋白水解产生，并且能够与VP16结合。
