Laboratory of Virology, Wageningen University, PO Box 629, 6700 AP Wageningen, The Netherlands.
J Gen Virol. 2010 Apr;91(Pt 4):907-14. doi: 10.1099/vir.0.018044-0. Epub 2009 Dec 2.
Cyclobutane pyrimidine dimer (CPD) photolyases convert UV-induced CPDs in DNA into monomers using visible light as the energy source. Two phr genes encoding class II CPD photolyases PHR1 and PHR2 have been identified in Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV). Transient expression assays in insect cells showed that PHR1-EGFP fusion protein was localized in the nucleus. Early after transfection, PHR2-EGFP was distributed over the cytoplasm and nucleus but, over time, it became localized predominantly in the nucleus. Immunofluorescence analysis with anti-PHR2 antiserum showed that, early after transfection, non-fused PHR2 was already present mainly in the nucleus, suggesting that the fusion of PHR2 to EGFP hindered its nuclear import. Both PHR-EGFP fusion proteins strongly colocalized with chromosomes and spindle, aster and midbody structures during host-cell mitosis. When PHR2-EGFP-transfected cells were superinfected with Autographa californica multiple-nucleocapsid NPV (AcMNPV), the protein colocalized with virogenic stroma, the replication factories of baculovirus DNA. The collective data support the supposition that the PHR2 protein plays a role in baculovirus DNA repair.
环丁烷嘧啶二聚体（CPD）光解酶利用可见光作为能量来源，将 DNA 中紫外线诱导的 CPD 转化为单体。在斜纹夜蛾多核型多角体病毒（ChchNPV）中已鉴定出编码 II 类 CPD 光解酶 PHR1 和 PHR2 的两个 phr 基因。在昆虫细胞中的瞬时表达试验表明，PHR1-EGFP 融合蛋白定位于细胞核中。转染后早期，PHR2-EGFP 分布于细胞质和细胞核，但随着时间的推移，它主要定位于细胞核中。用抗 PHR2 抗血清进行免疫荧光分析表明，转染后早期，非融合的 PHR2 主要已存在于细胞核中，表明 PHR2 与 EGFP 的融合阻碍了其核输入。在宿主细胞有丝分裂过程中，两种 PHR-EGFP 融合蛋白均与染色体、纺锤体、星体和中体结构强烈共定位。当 PHR2-EGFP 转染的细胞被美洲棉铃虫多核多角体病毒（AcMNPV）超感染时，该蛋白与病毒质，即杆状病毒 DNA 的复制工厂共定位。这些数据共同表明，PHR2 蛋白在杆状病毒 DNA 修复中发挥作用。
