Fuller C M, Collins M S, Easton A J, Alexander D J
Virology Department, Veterinary Laboratories Agency, Addlestone, Surrey, UK.
Arch Virol. 2007;152(8):1575-82. doi: 10.1007/s00705-007-0963-8. Epub 2007 May 21.
Viruses with intracerebral pathogenicity indices (ICPIs) of 0.025, 0.55, 1.013 and 1.3. were cloned from a PPMV-1 isolate with an ICPI of 0.32 by passage in embryonated fowls' eggs. Deduced amino acid sequences of the haemagglutinin-neuraminidase (HN) and precursor fusion proteins (F0) showed them to have only a single amino acid difference: those with an ICPI value <0.7 had proline at amino acid position 453 of the F0 protein, and those with an ICPI value >0.7 contained a serine. The virus with an ICPI of 0.025 was further passaged, and the ICPI of non-cloned virus increased to 0.76/0.79, which was then reduced to 0.49 on cloning. The proline at residue 453 was retained, but there were two nucleotide changes in the virus of ICPI 0.49, T --> C at position 1769 in the untranslated region of the fusion gene and G --> A at position 437 of the HN gene, resulting in the amino acid change G --> R at position 116 in the HN protein.
从一株脑内致病指数（ICPI）为0.32的禽副粘病毒1型（PPMV-1）分离株通过在鸡胚中传代，克隆出了ICPI分别为0.025、0.55、1.013和1.3的病毒。血凝素神经氨酸酶（HN）和融合前体蛋白（F0）的推导氨基酸序列显示它们仅有一个氨基酸差异：ICPI值<0.7的病毒在F0蛋白的第453位氨基酸为脯氨酸，而ICPI值>0.7的病毒含有丝氨酸。对ICPI为0.025的病毒进一步传代，未克隆病毒的ICPI增加到0.76/0.79，克隆后又降至0.49。第453位的脯氨酸得以保留，但ICPI为0.49的病毒有两个核苷酸变化，融合基因非编码区第1769位由T变为C，HN基因第437位由G变为A，导致HN蛋白第116位氨基酸由G变为R。
