Tong-Yun Wang,Guo-Ju Sang,Qian Wang,Chao-Liang Leng,Zhi-Jun Tian,Jin-Mei Peng,Shu-Jie Wang,Ming-Xia Sun,Fan-Dan Meng,Hao Zheng,Xue-Hui Cai,Yan-Dong Tang

Viruses.2022 Mar 10;14(3):572.doi: 10.3390/v14030572.

Abstract

Despite many efforts and diverse approaches, developing an effective herpesvirus vaccine remains a great challenge. Traditional inactivated and live-attenuated vaccines always raise efficacy or safety concerns. This study used Pseudorabies virus (PRV), a swine herpes virus, as a model. We attempted to develop a live but replication-incompetent PRV by genetic code expansion (GCE) technology. Premature termination codon (PTC) harboring PRV was successfully rescued in the presence of orthogonal system MbpylRS/tRNAPyl pair and unnatural amino acids (UAA). However, UAA incorporating efficacy seemed extremely low in our engineered PRV PTC virus. Furthermore, we failed to establish a stable transgenic cell line containing orthogonal translation machinery for PTC virus replication, and we demonstrated that orthogonal tRNAPyl is a key limiting factor. This study is the first to demonstrate that orthogonal translation system-mediated amber codon suppression strategy could precisely control PRV-PTC engineered virus replication. To our knowledge, this is the first reported PTC herpesvirus generated by GCE technology. Our work provides a proof-of-concept for generating UAAs-controlled PRV-PTC virus, which can be used as a safe and effective vaccine.

Keywords: genetic code expansion; premature termination codon; pseudorabies virus.