Institute of Insect Sciences and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Kaixuan Road 268, Hangzhou 310029, People's Republic of China.
Mol Biol Rep. 2011 Mar;38(3):2141-9. doi: 10.1007/s11033-010-0341-6. Epub 2010 Sep 17.
Open reading frame 75 (Bm-p33) of Bombyx mori nucleopolyhedrovirus (BmNPV) is a homologue of Autographa californica multiple nucleopolyhedrovirus ORF92. The gene is conserved among all baculoviruses that have been completely sequenced to date and is considered to be a baculovirus core set gene. No amino acid mutation was found in Bm-p33 sequences among six BmNPV strains differing in geography, phenotype, or host. The Bm-p33 transcript can be detected as early as 12 h post infection (h p.i.) and remains detectable until 96 h p.i. The Bm-p33 protein was detected in cell lysates from 18 h p.i. through 96 h p.i., and no positive band could be detected in budded viruses (BVs) and occlusion-derived viruses (ODVs) by western blot using anti-Bm-p33 serum. Immunofluorescence microscopy indicated that Bm-p33 accumulated in the nuclear membrane and the intranuclear region, especially near the nuclear membrane of the virus-infected cells. Bm75 RNAi significantly decreased the mRNA level. However, no obvious effects on ODV formation and BV production in BmNPV-infected cells could be detected. Bm-p33 is a BmNPV late gene encoding a nonstructural protein which may function mainly in the nucleus of the infected cells.
家蚕核多角体病毒（BmNPV）的开放阅读框 75（Bm-p33）是美洲棉铃虫多角体病毒 ORF92 的同源物。该基因在家蚕核多角体病毒的所有已完全测序的病毒中都保守，被认为是一种杆状病毒核心组基因。在地理、表型或宿主不同的 6 株 BmNPV 菌株中，Bm-p33 序列没有发现氨基酸突变。Bm-p33 转录本在感染后 12 小时（h p.i.）即可检测到，并可一直检测到 96 h p.i.。在感染后 18 h p.i.到 96 h p.i.，在细胞裂解物中可以检测到 Bm-p33 蛋白，而用抗 Bm-p33 血清进行的 Western blot 分析在芽生病毒（BVs）和出芽病毒（ODVs）中未检测到阳性条带。免疫荧光显微镜观察表明，Bm-p33 积累在核膜和核内区，特别是在病毒感染细胞的核膜附近。Bm75 RNAi 显著降低了 mRNA 水平。然而，在 BmNPV 感染的细胞中，对 ODV 形成和 BV 产生没有明显影响。Bm-p33 是 BmNPV 的晚期基因，编码一种非结构蛋白，可能主要在感染细胞的核内发挥作用。
