鸡抗病毒Mx基因的克隆与序列分析

Cloning and sequence analysis of chicken Mx gene with antiviral activity

用干扰素诱导剂poly（I）／（C）诱导鸡胚成纤维细胞，提取细胞总RNA，采用RT—PCR方法扩增了北京白鸡Mx基因全长编码区序列。序列分析表明：该基因编码区长2118bp，编码705个氨基酸残基，其第631位为天冬酰胺，理论上推测具有抗病毒活性。通过与GenBank中已登录的7个品系鸡Mx基因进行核苷酸系统进化树分析，结果显示，北京白鸡Mx基因与WL—N品系鸡Mx基因的亲缘关系最近。北京白鸡Mx基因序列与其他动物Mx基因序列的比较结果显示，核苷酸同源性为49．5％～76．8％，氨基酸同源性为44．1％～61．6％。据此可以推断：克隆的Mx基因具有抗病毒活性的分子特征和特征性功能结构，不同种属动物Mx基因的同源性与其亲缘关系呈正相关。

Full-length sequence of Beijing white chicken（BJ） Mx gene was amplified by RT-PCR from the total RNA extracted from chick embryo fibroblast（CEF） induced by poly（I）/（C）. Sequence analysis indicated that the chicken Mx gene contained an open reading frame（ORF） of 2 118 bp encoding a protein of 705 amino acids. The amino acid at position 631 ,which was deduced from the amplified Mx gene,was Asn. A phylogenetic tree based on Mx gene sequence was constructed. Results showed that chicken Mx gene sequence was polymorphic,and the amplified Mx gene had the lowest distance with the gene fi＇om WL-N strain available in GenBank. Analysis of homology showed that the chicken Mx gene and the deduced amino acids shared 49.5 %- 76.8% and 44.1%- 61.6% homology with those from other animals available in GenBank,respectively. It was concluded from the analysis that the amplified chicken Mx gene had antiviral molecular characteristics and functional construction, and homology of Mx gene was positively correlative with the phylogenetic relationship among different animal species.