The Effects of Targeting the Vaccinia Virus B5R Protein to the Endoplasmic Reticulum on Virus Morphogenesis and Dissemination

Journal article

The consequence of redirecting the vaccinia virus (VV) B5R protein to the endoplasmic reticulum (ER) has been investigated by the addition of an ER retrieval signal KKSL (K₂X₂) to the B5R C-terminus. This mutant B5R gene and a version of the gene with the inactive ER retrieval sequence KKSLAL (K₂X₄) were inserted into the thymidine kinase locus of a VV mutant lacking the B5R gene, vΔB5R. Similar levels of B5R protein were made by each virus, but the B5R-K₂X₂ protein remained sensitive to endoglycosidase H and colocalised with protein disulphide isomerase in the ER. In contrast, the B5R-K₂X₄ protein colocalised with 1,4-galactosyltransferase in the trans-Golgi network. Electron microscopy revealed that even when the B5R protein was redirected to the ER, intracellular mature virus particles were wrapped by cellular membranes to form intracellular enveloped virus particles, although more incompletely wrapped particles were evident compared with wild type. These intracellular enveloped virus particles were, however, unable to efficiently induce the polymerisation of actin and the plaque size formed by vB5R-K₂X₂ was small. Nevertheless, the amount and specific infectivity of EEV produced by vB5R-K₂X₂ were similar to those of wild type, despite the dramatic reduction in the amount of B5R protein present in vB5R-K₂X₂ EEV.

Authors: Mathew, E; Sanderson, C; Hollinshead, R; Hollinshead, M; Grimley, R

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wellcome Trust
• Journal: Virology
• Volume: 265
• Issue: 1
• Pages: 131–146
• Publication date: 1999-12-01
• Edition: Publisher's version
• DOI: 10.1006/viro.1999.0023
• Language: English
• Keywords: endoplasmic reticulum; actin tails; B5R protein; plaque size; vaccinia virus; extracellular enveloped virus; electron microscopy
• Subjects: Vaccinology; Viruses