The Effect Of Bombyx Mori BmRad23 On UV-damaged BmNPV

Nucleotide excision repair(NER)is a very important DNA damage repair pathway that can repair UV-induced DNA damage and has been extensively studied.Rad23 protein participates in the recognition process of damage sites and is a very important repair protein in NER.The protein has been studied in yeast and humans,but little in silkworm.In this paper,the subcellular localization and function of BmRad23 were preliminarily analyzed.Furthermore,the interaction of ultraviolet radiation,Bombyx mori multiple nucleopolyhedrovirus(BmNPV)and silkworm cells was analyzed.The effect of BmRad23 on the proliferation of BmNPV was analyzed by overexpressing BmRad23 and constructing recombinant virus expressing BmRad23.The main findings are as follows:1.Firstly,we constructed the plasmid for expressing the fusion protein BmRad23-egfp.BmRad23 was mainly localized in the nucleus by transient transfection.Host cell reaction experiments show that overexpression of BmRad23 can help UV-damaged reporter gene2.Next we analyzed the effect of BmNPV,UV and silkworm cells.The results showed that ultraviolet radiation reduced cell activity,promoted cell apoptosis,and decreased virus titer.At the same time,UV-damaged BmN cells were not conducive to the proliferation of BmNPV.However,after higher doses of UV treatment,BmNPV-infected cells were more active than non-infected cells and showed a lower degree of apoptosis.RT-qPCR experiments further revealed that the expression of DNA repair-related genes were significantly increased if BmNPV or B.mori cells were irradiated with UV light.It is speculated that the silkworm and virus may utilize related proteins after UV irradiation to repair UV-induced DNA damage.However,UV-damaged BmN cells were not conducive to BmNPV proliferation.BmNPV may improve the ability of host cells to repair UV-induced damage as soon as possible to maintain a better status for viral proliferation.At the same time,qPCR experiments results showed that the mRNA levels of BmRad23 and BmRad4 were significantly increased after BmNPV infection,suggesting that these proteins may be utilized in the replication and proliferation of BmNPV.3.Furthermore,the results of qPCR revealed that the overexpression ofBmRad23 promoted the mRNA levels of BmRad4 and Bm65 that were DNA repair-related genes,but had little affect on the mRNA levels of Bombyxin..It is speculated that BmRad23 can promote the repair of UV-induced damage in silkworm and BmNPV by affecting the expression of other DNA repair-related genes.Furthermore,the RT-qPCR results showed that the expression of BmRad23 and BmRad4 was similar in Bm65-deficient virus infected cells and control virus infected cells.When the host cells or the two viruses were damaged by UV,the mRNA of BmRad23 and BmRad4 in the control virus-infected cells was significantly higher than that in Bm65-deficient virus infected cells.We speculate that the viral protein Bm65 can also help repair the UV damage of the host and BmNPV by affecting the expression of DNA repair-related genes in the silkworm.4.Finally,we overexpressed BmRad23 and found that it was beneficial to BmNPV proliferation,and also beneficial to the repair of UV-damaged BmNPV.Next,we constructed a recombinant virus of expressing BmRad23.The viral titer analysis indicated that the recombinant baculovirus inserted with the repair gene BmRad23 had increased activity and enhanced resistance to UV.This article indicates that the NER repair protein BmRad23 might repair the UV-damaged BmNPV and provide a theoretical basis for the transformation of new and highly efficient baculovirus biocides.At the same time,after UV irradiation,the DNA repair-related genes of Bombyx mori and BmNPV interacted with each other to help repair the UV damage of host and virus,which provided a reference for further exploring the mutual game relationship between baculovirus and host in evolution.