Liu Q, Hintz M, Li J, Linder M, Geyer R, Hobom G
Institut für Mikrobiologie und Molekularbiologie der Universität Giessen, Federal Republic of Germany.
Arch Virol. 2000;145(6):1211-23. doi: 10.1007/s007050070120.
Among two pairs of agnoproteins encoded in upstream positions in the late mRNAs of avian polyomavirus BFDV, either agno-1a or its splice derivative agno-1b are required for viral propagation. Out of the two proteins both of which consist of multiple electrophoretic subspecies, the smaller and less complex agno-1b has been cDNA-cloned into an influenza-virus /RNA-polymerase I expression system for production of higher amounts of this protein in infected chicken embryo fibroblasts. Fractional modification of agno-1b by phosphorylation at residues serine 51, serine 53, and threonine 73 is demonstrated through dephosphorylation by alkaline phosphatase, mass spectrometry of individual protein species isolated by strong anion exchange chromatography, and single or multiple alanine substitutions of serine or threonine residues in site-directed mutagenesis.
在禽多瘤病毒BFDV晚期mRNA上游位置编码的两对agno蛋白中，病毒传播需要agno-1a或其剪接衍生物agno-1b。这两种蛋白均由多个电泳亚类组成，其中较小且结构较简单的agno-1b已被cDNA克隆到流感病毒/RNA聚合酶I表达系统中，以便在感染的鸡胚成纤维细胞中产生更多量的这种蛋白。通过碱性磷酸酶去磷酸化、强阴离子交换色谱分离的单个蛋白种类的质谱分析以及定点诱变中丝氨酸或苏氨酸残基的单或多个丙氨酸取代，证实了agno-1b在丝氨酸51、丝氨酸53和苏氨酸73残基处的磷酸化修饰。
