Bera Bidhan Ch, Shanmugasundaram K, Barua Sanjay, Anand Taruna, Riyesh T, Vaid Rajesh K, Virmani Nitin, Bansal Manish, Shukla Brihaspati N, Malik Praveen, Singh Raj K
Veterinary Type Culture Collection, National Research Centre on Equines, Sirsa Road, Hisar, Haryana, India.
Virus Genes. 2012 Dec;45(3):488-98. doi: 10.1007/s11262-012-0788-8. Epub 2012 Aug 8.
Buffalopox virus (BPXV), a close variant of vaccinia virus (VACV) has emerged as a zoonotic pathogen. The host tropism of poxviruses is governed by host-range genes. Among the host-range genes: E3L, K3L, and C7L are essential for virus replication by preventing interferon resistance, whereas B5R is essential for spread of the virus and evasion from the host's immune response as in VACV. We report sequence analysis of host-range genes: E3L, K3L, C7L, and membrane protein gene (B5R) of BPXVs from buffalo, cattle, and human from recent outbreaks in India-their phylogenetic relationship with reference strain (BP4) and other Orthopoxviruses. BPXVs revealed a sequence homology with VACVs including zoonotic Brazilian VACV-like viruses. The aa sequences of E3L and K3L genes were 100 % similar in buffalo, cattle, and human isolates. However, four significant point mutations (I11K; N12K and S36F in C7L gene and D249G in B5R gene) were observed specific to buffalo isolate only. This signifies that different strains of BPXV were circulated during the outbreak. The mutations in C7L and B5R could play an important role in adaptation of BPXV in human and cattle which needs further functional studies. The strain of BPXV isolated from buffalo may not be adopted in human and cow. Various point mutations were observed in the host-range genes of reference strain (BPXV-BP4) which may be due to several passages of virus in cell culture. The phylogeny constructed based on concatenated gene sequences revealed that BPXVs are not as closely related to vaccine strain (Lister and Lister-derived strain-LC16m8), as hypothesized earlier, rather they are more closely related to reference strain (BPXV-BP4) and other vaccinia and vaccinia-like viruses such as Passatempo and Aracatuba viruses. The availability of information regarding host tropism determinants would allow us to understand molecular mechanism of species tropism of poxviruses which would be useful in unveiling new strategies to control zoonotic poxviral infections.
水牛痘病毒（BPXV）是痘苗病毒（VACV）的一个紧密变种，已成为一种人畜共患病原体。痘病毒的宿主嗜性由宿主范围基因决定。在宿主范围基因中：E3L、K3L和C7L通过防止干扰素抗性对病毒复制至关重要，而B5R对病毒传播和逃避宿主免疫反应至关重要，就像在痘苗病毒中一样。我们报告了来自印度近期疫情的水牛、牛和人类的BPXV宿主范围基因E3L、K3L、C7L和膜蛋白基因（B5R）的序列分析——它们与参考菌株（BP4）和其他正痘病毒的系统发育关系。BPXV显示出与痘苗病毒包括人畜共患的巴西痘苗病毒样病毒的序列同源性。水牛、牛和人类分离株中E3L和K3L基因的氨基酸序列100%相似。然而，仅在水牛分离株中观察到四个显著的点突变（C7L基因中的I11K、N12K和S36F以及B5R基因中的D249G）。这表明在疫情期间BPXV的不同菌株在传播。C7L和B5R中的突变可能在BPXV在人和牛中的适应中起重要作用，这需要进一步的功能研究。从水牛分离的BPXV菌株可能不适用于人和牛。在参考菌株（BPXV - BP4）的宿主范围基因中观察到各种点突变，这可能是由于病毒在细胞培养中的多次传代。基于串联基因序列构建的系统发育表明，BPXV与疫苗株（李斯特菌和李斯特菌衍生株 - LC16m8）并不像之前假设的那样密切相关，相反，它们与参考菌株（BPXV - BP4）以及其他痘苗病毒和痘苗病毒样病毒如帕萨特姆波病毒和阿拉卡图巴病毒关系更密切。关于宿主嗜性决定因素的信息可用性将使我们能够理解痘病毒物种嗜性的分子机制，这将有助于揭示控制人畜共患痘病毒感染的新策略。
