Nyborg J K, Dynan W S
Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309.
J Biol Chem. 1990 May 15;265(14):8230-6.
Nuclear extracts of cultured human cells contain multiple proteins that recognize specific sequence elements within the transcriptional control region of the human retrovirus, human T-cell leukemia virus type I (HTLV-I). Here we report the purification of host expression factor 1T (HEF-1T), a DNA-binding protein from human T-lymphocytes that binds to each of the three 21-base pair repeat enhancer elements in the proviral long terminal repeats of HTLV-I and the related virus, HTLV-II. HEF-1T is composed of two polypeptides of 41 and 59 kDa. We show that HEF-1T is distinct from a second protein, present in non-lymphoid cells, that binds to overlapping sites in and near the 21-base pair repeats. This second protein is composed of a single 47-kDa polypeptide and appears to be identical to the previously described transcription factor AP-2. A third protein, also distinct from HEF-1T, binds within the first repeat. The present results suggest that there may be multiple modes of HTLV-I promoter recognition involving distinct sets of cellular proteins.
培养的人类细胞的核提取物含有多种蛋白质，这些蛋白质可识别人类逆转录病毒——I型人类T细胞白血病病毒（HTLV-I）转录控制区域内的特定序列元件。在此，我们报告了宿主表达因子1T（HEF-1T）的纯化，它是一种来自人类T淋巴细胞的DNA结合蛋白，可与HTLV-I及相关病毒HTLV-II前病毒长末端重复序列中的三个21碱基对重复增强子元件中的每一个结合。HEF-1T由41 kDa和59 kDa的两种多肽组成。我们发现HEF-1T与存在于非淋巴细胞中的第二种蛋白不同，后者可与21碱基对重复序列及其附近的重叠位点结合。第二种蛋白由单一的47 kDa多肽组成，似乎与先前描述的转录因子AP-2相同。第三种蛋白也与HEF-1T不同，它结合在第一个重复序列内。目前的结果表明，HTLV-I启动子识别可能存在多种模式，涉及不同组的细胞蛋白。
