Tanaka J, Sadanari H, Sato H, Fukuda S
Department of Virology, Kanazawa University, Japan.
Virology. 1991 Nov;185(1):271-80. doi: 10.1016/0042-6822(91)90774-6.
Replication of human cytomegalovirus (HCMV) in a human epithelial thyroid papillary carcinoma cell line (TPC-1) was restricted. However, pretreatment of these cells with 5 mM sodium butyrate (NaB) for 24 hr before infection enhanced both HCMV yield and infectious center titer to a similar level of that seen in human embryonic lung fibroblast cells. Immunofluorescence staining, gel electrophoresis, and Northern blot analysis revealed that TPC-1 cells are nonpermissive for expression of HCMV major immediate early (IE1) functions, but many of the cells become permissive after being treated with NaB. The presence of cycloheximide during NaB pretreatment of the cells efficiently diminished the stimulatory effect of NaB on expression of the IE1 gene. Therefore, it appeared that NaB induces the synthesis of a cellular protein(s) which apparently plays an important role in the conversion of nonpermissive cells to a permissive state for expression of this critical viral gene. Transient chloramphenicol acetyltransferase (CAT) assay experiments indicated that in TPC-1 cells the HCMV-CAT construct which contains the complete IE1 promoter regulatory region was expressed poorly, whereas a high level of CAT activity was detectable in the NaB-treated cells. Therefore, these results suggest that the enhancing effect of NaB on HCMV replication is expressed through some host cellular factor(s), and the HCMV IE1 promoter regulatory region is most likely to be the primary target of NaB action.
人巨细胞病毒（HCMV）在人甲状腺乳头状癌细胞系（TPC-1）中的复制受到限制。然而，在感染前用5 mM丁酸钠（NaB）预处理这些细胞24小时，可使HCMV产量和感染中心滴度提高到与人类胚胎肺成纤维细胞中所见相似的水平。免疫荧光染色、凝胶电泳和Northern印迹分析显示，TPC-1细胞对HCMV主要立即早期（IE1）功能的表达不敏感，但许多细胞在用NaB处理后变得敏感。在细胞用NaB预处理期间存在环己酰亚胺可有效降低NaB对IE1基因表达的刺激作用。因此，似乎NaB诱导了一种细胞蛋白的合成，该蛋白显然在将非敏感细胞转化为对该关键病毒基因表达敏感的状态中起重要作用。瞬时氯霉素乙酰转移酶（CAT）分析实验表明，在TPC-1细胞中，含有完整IE1启动子调控区的HCMV-CAT构建体表达不佳，而在NaB处理的细胞中可检测到高水平的CAT活性。因此，这些结果表明，NaB对HCMV复制的增强作用是通过一些宿主细胞因子表达的，并且HCMV IE1启动子调控区很可能是NaB作用的主要靶点。
