Improving Baculovirus Transduction of Mammalian Cells by Incorporation of Thogotovirus Glycoproteins
Baculovirus can transduce a wide range of mammalian cells and is considered a promising gene therapy vector. However, the low transduction efficiency of baculovirus into many mammalian cells limits its practical application. Co-expressing heterologous viral glycoproteins (GPs), such as vesicular stomatitis virus G protein (VSV G), with baculovirus native envelope protein GP64 is one of the feasible strategies for improving virus transduction. Tick-borne thogotoviruses infect mammals and their GPs share sequence/structure homology and common evolutionary origins with baculovirus GP64. Herein, we tested whether thogotovirus GPs could facilitate the entry of the prototype baculovirus Autographa californica multiple multiple nucleopolyhedrovirus (AcMNPV) into mammalian cells. The gp genes of two thogotoviruses, Thogoto virus and Dhori virus, were inserted into the AcMNPV genome. Both GPs were properly expressed and incorporated into the envelope of the recombinant AcMNPVs. The transduction rates of recombinant AcMNPVs expressing the two thogotovirus GPs increased for approximately 4–12 fold compared to the wild type AcMNPV in six of the 12 tested mammalian cell lines. It seemed that thogotovirus GPs provide the recombinant AcMNPVs with different cell tropisms and showed better performance in several mammalian cells compared to VSV G incorporated AcMNPV. Further studies showed that the improved transduction was a result of augmented virus-endosome fusion and endosome escaping, rather than increased cell binding or internalization. We found the AcMNPV envelope protein GP64-mediated fusion was enhanced by the thogotovirus GPs at relatively higher pH conditions. Therefore, the thogotovirus GPs represent novel candidates to improve baculovirus-based gene delivery vectors.
KeywordsAutographa californica multiple nucleopolyhedrovirus (AcMNPV) Baculovirus Thogotovirus Glycoprotein Transduction Mammalian cells
This work was supported by the grants from the National Natural Science Foundation of China (Grant Nos. 31370191 and 31621061), Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB11030400) and the National Key R&D Program of China (Grant No. 2018YFA0507200). We thank Dr. Ding Gao, Ms. Juan Min, Mr. He Zhao and Ms. Li Li from the Core Facility and Technical Support facility of the Wuhan Institute of Virology for technical assistance.
LH, YL, MW and HW designed the research; LH and YL performed research and analyzed data; LH and MW wrote the paper; FD, ZH and HW edited and commented on the manuscript.
Compliance with Ethical Standards
Conflict of interest
The authors declare no competing interests.
Animal and Human Rights Statement
This article does not contain any studies with human or animal subjects performed by any of the authors.
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