Gillespie F P, Doros L, Vitale J, Blackwell C, Gosselin J, Snyder B W, Wadsworth S C
TSI Corporation, Worcester, Massachusetts 01605.
Mol Cell Biol. 1993 May;13(5):2952-8. doi: 10.1128/mcb.13.5.2952-2958.1993.
The gene for the human CD4 glycoprotein, which serves as the receptor for human immunodeficiency virus type 1, along with approximately 23 kb of sequence upstream of the translational start site, was cloned. The ability of 5' flanking sequences to direct tissue-specific expression was tested in cell culture and in transgenic mice. A 5' flanking region of 6 kb was able to direct transcription of the CD4 gene in NIH 3T3 cells but did not result in detectable expression in the murine T-cell line EL4 or in four lines of transgenic mice. A larger 5' flanking region of approximately 23 kb directed high-level CD4 transcription in the murine T-cell line EL4 and in three independent lines of transgenic mice. Human CD4 expression in all tissues analyzed was tightly correlated with murine CD4 expression; the highest levels of human CD4 RNA expression were found in the thymus and spleen, with relatively low levels detected in other tissues. Expression of human CD4 protein in peripheral blood mononuclear cells was examined by flow cytometry in these transgenic animals and found to be restricted to the murine CD4+ subset of lymphocytes. Human CD4 protein, detected with an anti-human CD4 monoclonal antibody, was present on the surface of 45 to 50% of the peripheral blood mononuclear cells from all transgenic lines.
作为人类免疫缺陷病毒1型受体的人类CD4糖蛋白基因，连同翻译起始位点上游约23 kb的序列一起被克隆。在细胞培养和转基因小鼠中测试了5'侧翼序列指导组织特异性表达的能力。一个6 kb的5'侧翼区域能够在NIH 3T3细胞中指导CD4基因的转录，但在鼠T细胞系EL4或四系转基因小鼠中未检测到表达。一个约23 kb的更大的5'侧翼区域在鼠T细胞系EL4和三系独立的转基因小鼠中指导高水平的CD4转录。在所有分析的组织中，人类CD4的表达与鼠CD4的表达紧密相关；在胸腺和脾脏中发现人类CD4 RNA表达水平最高，在其他组织中检测到的水平相对较低。通过流式细胞术在这些转基因动物中检测外周血单核细胞中人类CD4蛋白的表达，发现其仅限于淋巴细胞的鼠CD4+亚群。用抗人类CD4单克隆抗体检测到的人类CD4蛋白存在于所有转基因系45%至50%的外周血单核细胞表面。
