Pappu S S, Febres V J, Pappu H R, Lee R F, Niblett C L
Plant Pathology Department, University of Florida, Gainesville 32611-0680, USA.
Virus Res. 1997 Jan;47(1):51-7. doi: 10.1016/s0168-1702(96)01405-0.
The 3' proximal open reading frame (ORF 11) in the citrus tristeza virus (CTV) genome potentially encodes a protein of 209 amino acids with an estimated molecular weight of 23 kDa (p23). The p23 ORF from the severe Florida strain T36 of CTV was expressed in Escherichia coli, and the expressed protein was used to raise polyclonal antibodies in a rabbit. Using these antisera on a Western blot, a protein of expected size (23 kDa) was detected in tissue extracts from CTV-infected citrus but not from uninfected citrus. Most of the p23 protein was found in the soluble, cytoplasmic fraction. Comparison of the sequence of p23 genes from several biologically and geographically diverse CTV isolates indicated a high degree of conservation for this gene and for the RNA binding motif in particular. A cluster dendrogram of the deduced amino acid sequences correlated with the biological properties of the isolates, forming distinct groups of mild, quick decline on stem pitting-inducing isolates. Therefore it is possible that, in addition to the capsid protein gene, the p23 gene also may serve as an indicator for disease severity.
柑橘衰退病毒（CTV）基因组中的3'近端开放阅读框（ORF 11）可能编码一种含有209个氨基酸的蛋白质，估计分子量为23 kDa（p23）。来自CTV佛罗里达严重株系T36的p23 ORF在大肠杆菌中表达，表达的蛋白质用于在兔体内制备多克隆抗体。在蛋白质免疫印迹中使用这些抗血清，在CTV感染的柑橘组织提取物中检测到预期大小（23 kDa）的蛋白质，但在未感染的柑橘中未检测到。大部分p23蛋白存在于可溶性细胞质部分。对来自几个生物学和地理上不同的CTV分离株的p23基因序列进行比较表明，该基因特别是RNA结合基序具有高度保守性。推导氨基酸序列的聚类树状图与分离株的生物学特性相关，形成了温和、快速衰退和茎陷点诱导分离株的不同组。因此，除衣壳蛋白基因外，p23基因也有可能作为疾病严重程度的指标。
