Black A C, Luo J, Chun S, Bakker A, Fraser J K, Rosenblatt J D
Virus Genes. 1996;12(3):275-85. doi: 10.1007/BF00284648.
The human immunodeficiency virus (HIV) Rev and human T-cell leukemia virus (HTLV) Rex proteins regulate viral RNA processing. Both proteins act to overcome the block to viral structural gene expression, at least in part, by reversing the inhibitory effect of intronic RNA sequences, termed cis-acting repressive (CRS) sequences. Using HTLV type II (HTLV-II) as a model, we recently showed that the function of a 5' long terminal repeat (LTR) CRS correlates with in vitro binding by both polypyrimidine tract binding (PTB) protein (also known as hnRNP I) and hnRNP A1 to CRS RNA (1,2). Using radioimmunoprecipitation of proteins ultraviolet (UV) crosslinked to each HIV CRS RNA with monoclonal anti-hnRNP antibodies, we now demonstrate that hnRNP I and hnRNP A1 bind to two different HIV-1 CRS RNAs. In addition, we show that hnRNP I and hnRNP A1 binding to HIV-1 CRS RNAs can be specifically competed by HTLV-II CRS RNAs using electrophoretic mobility shift assay (EMSA)/UV crosslinking assays. Binding by both hnRNP I and hnRNP A1 to HIV-1 and HTLV-II CRS RNAs suggests a role for these proteins in CRS function that may be influenced by the Rev and Rex proteins, respectively.
人类免疫缺陷病毒（HIV）的Rev蛋白和人类T细胞白血病病毒（HTLV）的Rex蛋白可调节病毒RNA的加工过程。这两种蛋白至少部分地通过逆转内含子RNA序列（称为顺式作用抑制序列，CRS）的抑制作用，来克服对病毒结构基因表达的阻碍。以II型人类嗜T淋巴细胞病毒（HTLV-II）为模型，我们最近发现5'长末端重复序列（LTR）CRS的功能与多嘧啶序列结合蛋白（PTB，也称为hnRNP I）和hnRNP A1与CRS RNA的体外结合相关（1,2）。通过使用单克隆抗hnRNP抗体对与每种HIV CRS RNA进行紫外线（UV）交联的蛋白质进行放射免疫沉淀，我们现在证明hnRNP I和hnRNP A1与两种不同的HIV-1 CRS RNA结合。此外，我们表明，使用电泳迁移率变动分析（EMSA）/UV交联分析，HTLV-II CRS RNA可以特异性竞争hnRNP I和hnRNP A1与HIV-1 CRS RNA的结合。hnRNP I和hnRNP A1与HIV-1和HTLV-II CRS RNA的结合表明，这些蛋白在CRS功能中发挥作用，而这可能分别受Rev和Rex蛋白的影响。
