鸡减蛋综合征病毒DNA结合蛋白的基因结构及同源分析

Sequencing Analysis of DNA Binding Protein of an Avirulent Strain (AA 2) of EDSV

从中国发病鸡群中分离的鸡减蛋综合征病毒（ＥＤＳＶ）ＡＡ－２株，经常规方法提取其病毒核酸后，构建了限制性内切酶ＰｓｔⅠ及ＨｉｎｄⅢ水解片段的基因文库。对其中ＨｉｎｄⅢ－Ｆ片段（５２．９～５８．９ｍｕ）的正反２条链的序列测定发现，其反链存在１个编码容量为３８７个氨基酸（ａａ）的开放读码框架（ｏｐｅｎｒｅａｄｉｎｇｆｒａｍｅ，ＯＲＦ），经Ｇｅｎｅｂａｎｋ／ＥＭＢＬ同源搜寻后证实其编码产物为ＥＤＳＶ的ＤＮＡ结合蛋白（ＤＢＰ）。与其他腺病毒ＤＢＰ的氨基酸序列进行同源比较，其Ｎ端同源性在１９．０％～４６．２％之间，Ｃ端同源性在２７．７％～６０．４％之间。腺病毒ＤＢＰ的３个保守序列ＣＲ１，ＣＲ２，ＣＲ３在ＥＤＳＶＤＢＰ中有较大变化，但ＥＤＳＶＤＢＰ的锌指框架（Ｚｎ２＋ｆｉｎｇｅｒｍｏｔｉｆ）却保留了对其功能必需的残基。

The library of the whole genome of an avirulent strain (AA 2) of EDSV isolated from China has been constructed in the type of Hind Ⅲ and Pst Ⅰ subclones respectively. Both strands of the Hind Ⅲ F segment (52.9 58.9 mu) encoding the open reading frame of the DNA binding protein were sequenced. Compared with the amino acid sequence of DBPs from other adenoviruses, the N domain and the C domain of the DBPs shared 19.0% 46.2% and 27.7% 60.4% similarities respectively. Futhermore, the EDSV DBP showed differences in the conserved regions CR1, CR2 and CR3, while retaining important residues for a putative zinc finger (Zf) motif.