Van Heuvel M, Bosveld I J, Klaassen P, Zwarthoff E C, Trapman J
Department of Pathology, Erasmus University, Rotterdam, The Netherlands.
J Interferon Res. 1988 Feb;8(1):5-14. doi: 10.1089/jir.1988.8.5.
As described earlier the protein products of the murine interferon (IFN) genes MuIFN-alpha 1, -alpha 2, and -alpha 4 differ in their antiviral activity on hamster (CHO) and mouse (L929) cells. For structure-function analysis, hybrids were prepared between the three genes using common restriction enzyme sites. Natural and hybrid genes were transiently expressed in monkey COS cells. Under the conditions used IFN constituted 20-30% of the total amount of secreted proteins. Using a panel of hybrids either between alpha 1 and alpha 2 or between alpha 1, alpha 2, and alpha 4, the amino-terminal region of the protein, from amino acids 10 to 58, was found to determine its antiviral activity on hamster cells. On mouse cells, the antiviral activities of hybrids between alpha 4 and either alpha 1 or alpha 2 were compared. The high activity of alpha 4 (five to ten times that of alpha 1 or alpha 2) was not transmitted to hybrids having the amino-terminal part of alpha 4, but coincided with the presence of the alpha 4 carboxy-terminal region in all but one hybrid construct. The deletion of five amino acids (positions 103-107) located in this region of alpha 4 did not affect antiviral activity when introduced into MuIFN-alpha 2 and a MuIFN-alpha 42 hybrid by site-directed mutagenesis.
如前所述，小鼠干扰素（IFN）基因MuIFN-α1、-α2和-α4的蛋白质产物对仓鼠（CHO）细胞和小鼠（L929）细胞的抗病毒活性有所不同。为了进行结构-功能分析，利用共同的限制性酶切位点在这三个基因之间构建了杂种基因。天然基因和杂种基因在猴COS细胞中瞬时表达。在所使用的条件下，IFN占分泌蛋白总量的20%-30%。使用一组α1和α2之间或α1、α2和α4之间的杂种基因，发现蛋白质从氨基酸10至58的氨基末端区域决定其对仓鼠细胞的抗病毒活性。在小鼠细胞上，比较了α4与α1或α2之间杂种基因的抗病毒活性。α4的高活性（是α1或α2的五至十倍）并未传递给具有α4氨基末端部分的杂种基因，而是与除一个杂种构建体之外的所有杂种构建体中α4羧基末端区域的存在一致。当通过定点诱变将位于α4这一区域的五个氨基酸（第103-107位）缺失引入MuIFN-α2和一个MuIFN-α42杂种基因时，并未影响抗病毒活性。
