Laimins L A, Gruss P, Pozzatti R, Khoury G
J Virol. 1984 Jan;49(1):183-9. doi: 10.1128/JVI.49.1.183-189.1984.
A series of recombinant molecules were constructed which direct the expression of the easily assayed gene chloramphenicol acetyltransferase. We have used these recombinants to show that the 73/72-base-pair tandem repeat unit from the Moloney murine sarcoma virus long terminal repeat shares a number of properties with the prototypic enhancer element, the simian virus 40 72-base-pair repeat. Specifically, the Moloney murine sarcoma virus sequence significantly enhances the level of gene expression at both 5' and 3' locations and in either orientation relative to the test gene. It is able to enhance gene activity both from its own promoter and from a heterologous (simian virus 40) promoter. The 73/72-base-pair subunits of the Moloney murine sarcoma virus enhancer differ in sequence by four nucleotides and also in the strength of their enhancer function. The promoter distal A repeat is at least three times as active as the promoter proximal B repeat in enhancing chloramphenicol acetyltransferase expression. Results of these studies also show that the enhancer sequence alone is unable to induce gene activity but requires other promoter elements, including a proximal GC-rich sequence and the Goldberg-Hogness box.
构建了一系列指导易于检测的氯霉素乙酰转移酶基因表达的重组分子。我们利用这些重组体表明，莫洛尼鼠肉瘤病毒长末端重复序列中的73/72碱基对串联重复单元与原型增强子元件猿猴病毒40的72碱基对重复序列具有许多共同特性。具体而言，莫洛尼鼠肉瘤病毒序列在相对于测试基因的5'和3'位置以及任一方向上均显著提高基因表达水平。它既能从自身启动子也能从异源（猿猴病毒40）启动子增强基因活性。莫洛尼鼠肉瘤病毒增强子的73/72碱基对亚基在序列上相差四个核苷酸，其增强子功能的强度也有所不同。在增强氯霉素乙酰转移酶表达方面，启动子远端的A重复序列的活性至少是启动子近端的B重复序列的三倍。这些研究结果还表明，单独的增强子序列无法诱导基因活性，而是需要其他启动子元件，包括近端富含GC的序列和戈德堡-霍格内斯盒。
