鸡传染性喉气管炎病毒WG株ICP4基因的鉴定及其在潜伏位点的表达

根据传染性喉气管炎病毒(Infectious laryngotracheitis virus,ILTV)SA-2株ICP4基因序列设计并合成3对引物,以ILTV中国王岗株(WG)DNA为模板扩增ICP4基因,并对其进行了序列测定。将ILTV WG株的ICP4基因及其推导的氨基酸序列,分别与ILTV SA-2株、BHV-1、EHV-1、EHV-4、MDV-1、MDV-2、HVT、PRV、VZV、HSV-1和HSV-2的ICP4基因及其推导的氨基酸序列比较后发现,ILTV毒株之间ICP4基因相对保守,核苷酸和氨基酸水平的同源性分别为99.7%和99.1%,但与其它α-疱疹病毒的ICP4基因的同源性则较低,低于3.0%。对潜伏感染鸡三叉神经节中病毒基因的检测显示,在人工感染ILTV WG株后第10 d～60 d内均能检测到ICP4特异RNA,而gB、gC、TK则未能检出。鉴于目前国内外对α-疱疹病毒潜伏感染相关基因以及ICP4基因序列和结构功能的研究,ILTV WG株ICP4基因的克隆和序列测定,以及病毒基因在潜伏感染鸡三叉神经节中的差异表达,为进一步研究ICP4基因的功能及确定潜伏感染相关基因奠定了基础。

Characterization of infectious laryngotracheitis virus WG strain ICP4 gene and expression in latency site

Three pair of primers flanking the ICP4 gene was designed according to the published nucleotide sequence of the ILTV strain SA2.The ICP4 gene of the ILTV Chinese Wanggang strain(WG)was obtained by PCR and sequenced.Nucleotide sequence and the deduced amino acid of the WG ICP4 gene were compared with that of ILTV strain SA2,BHV-1,EHV-1, EHV-4,MDV-1,MDV-2,HVT,PRV,VZV,HSV-1 and HSV-2.The results showed that the ICP4 gene was relatively conserved among different ILTV strains with 99.7% and 99.1% homologies in nucleotide sequence and the deduced amino acid sequence,respectively.However the ICP4 gene between different Alphaherpesvirus were highly variable with less than 3.0% sequence homology.Detection of virus gene in latently infected trigeminal ganglia(TG)indicated that ICP4-specific RNA was present on days 10 to 60 after infection with ILTV strain WG,but gB,gC and TK specific RNA was absent.The results on sequence and expression patterns of ICP4 gene of the ILTV WG strain in latently infected trigeminal ganglia reported here provide a framework for further study on the function of ICP4 gene and latency-related genes.