Pseudotyping lentiviral vectors for transduction of Salmo salar cells using glycoprotein from infectious salmon anaemia virus

Abstract

Lentivirus is commonly used as vector for CRISPR applications. The common vector system utilises glycoproteins from the vesicular stomatitis virus (VSV-G). This vector has broad a tropism, including the salmonid species Oncorhynchus tshawytscha (Chinook salmon). However, the existing vectors are not able to transfect Salmo salar (Atlantic salmon), which is an economically important species.

In this work, the compatibility of lentivirus and Salmo salar cells were attempted improved by altering the transduction conditions of VSV-G based lentivirus and by pseudotyping using glycoproteins from the infectious salmon anaemia virus (ISAV). None of the pseudotyped vectors succeeded in transfection of the salmon cells, but the ISAV pseudotyped vector was able to transduce the control human cells, which was unexpected.

As no transduction of Salmo salar cells were achieved, an understanding of where in the transduction the vector falls short was attempted. The internalisation patterns were explored by labelling the virus and observing the infection using confocal microscopy. Reverse transcriptase activity was evaluated by qPCR, and translation and GFP expression were tested through electroporation. The results found in this work indicate transduction is terminated after endosomal uptake and before reverse transcriptase, possibly due lack of viral escape leading to the degradation of the vectors.