Ko Jae-Hong, Jin Hee-Kyung, Asano Atsushi, Takada Ayato, Ninomiya Ai, Kida Hiroshi, Hokiyama Hironao, Ohara Mutsuo, Tsuzuki Masaoki, Nishibori Masahide, Mizutani Makoto, Watanabe Tomomasa
Laboratory of Experimental Animal Science, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
Genome Res. 2002 Apr;12(4):595-601. doi: 10.1101/gr.210702.
The nucleotide sequence of chicken Mx cDNA was reported earlier using the White Leghorn breed in Germany, but it showed no enhanced resistance to viruses. In this study, the nucleotide sequences of chicken Mx cDNA were determined in many breeds. A total of 25 nucleotide substitutions, of which 14 were deduced to cause amino acid exchanges, were detected, suggesting that the chicken Mx gene is very polymorphic. Transfected cell clones expressing chicken Mx mRNA were established after the Mx cDNA was constructed with an expression vector and introduced into mouse 3T3 cells, and the Mx genes from some breeds were demonstrated to confer positive antiviral responses to influenza virus and vesicular stomatitis virus. On the basis of the comparison among the antiviral activities associated with many Mx variations, a specific amino acid substitution at position 631 (Ser to Asn) was considered to determine the antivirally positive or negative Mx gene. Thus, a single amino acid substitution influences the antiviral activity of Mx in domesticated chickens.
此前曾报道过德国白来航鸡品种鸡Mx cDNA的核苷酸序列，但该序列并未表现出对病毒的增强抗性。在本研究中，测定了多个品种鸡Mx cDNA的核苷酸序列。共检测到25个核苷酸替换，其中14个被推断会导致氨基酸交换，这表明鸡Mx基因具有高度多态性。在用表达载体构建Mx cDNA并将其导入小鼠3T3细胞后，建立了表达鸡Mx mRNA的转染细胞克隆，并且已证明某些品种的Mx基因对流感病毒和水疱性口炎病毒具有阳性抗病毒反应。基于与多种Mx变异相关的抗病毒活性之间的比较，认为第631位的特定氨基酸替换（丝氨酸变为天冬酰胺）决定了Mx基因的抗病毒阳性或阴性。因此，单个氨基酸替换会影响家养母鸡中Mx的抗病毒活性。
