Ohta M, Nyunoya H, Tanaka H, Okamoto T, Akagi T, Shimotohno K
Virology Division, National Cancer Center Research Institute, Tokyo, Japan.
J Virol. 1988 Dec;62(12):4445-51. doi: 10.1128/JVI.62.12.4445-4451.1988.
The X gene products of the human T-cell leukemia viruses type I and II are thought to be involved not only in viral replication but also in mediating the expression of certain cellular genes. These X gene products are known to be translated from doubly spliced viral mRNA, while viral structural proteins, such as the gag, pol, and env gene products, are translated from unspliced or singly spliced viral mRNA. One of the X gene products of human T-cell leukemia virus type II, tax2 protein, has been shown to be responsible for transcriptional stimulation from the viral long terminal repeat. The other X gene product(s) of human T-cell leukemia virus type II, the rex2 protein(s), is located in the nuclear fraction of virus-infected cells, but its function is not known. This article reports evidence that rex2 protein(s) enhances the accumulation of unspliced viral RNA by interacting posttranscriptionally, either directly or indirectly, with a cis-regulatory element downstream from the first splice donor site in the long terminal repeat.
人们认为，人类I型和II型T细胞白血病病毒的X基因产物不仅参与病毒复制，还介导某些细胞基因的表达。已知这些X基因产物由双重剪接的病毒mRNA翻译而来，而病毒结构蛋白，如gag、pol和env基因产物，则由未剪接或单剪接的病毒mRNA翻译而来。人类II型T细胞白血病病毒的一种X基因产物，即tax2蛋白，已被证明可负责病毒长末端重复序列的转录激活。人类II型T细胞白血病病毒的其他X基因产物，即rex2蛋白，位于病毒感染细胞的核部分，但其功能尚不清楚。本文报道了rex2蛋白通过与长末端重复序列中第一个剪接供体位点下游的顺式调节元件进行转录后直接或间接相互作用，从而增强未剪接病毒RNA积累的证据。
