The envelope of intracellular African swine fever virus is composed of a single lipid bilayer.
African swine fever virus (ASFV) is a member of a family of large nucleocytoplasmic DNA viruses that include poxviruses, iridoviruses, and phycodnaviruses. Previous ultrastructural studies of ASFV using chemical fixation and cryosectioning for electron microscopy (EM) have produced uncertainty over whether the inner viral envelope is composed of a single or double lipid bilayer. In this study we prepared ASFV-infected cells for EM using chemical fixation, cryosectioning, and high-pressure freezing. The appearance of the intracellular viral envelope was determined and compared to that of mitochondrial membranes in each sample. The best resolution of membrane structure was obtained with samples prepared by high-pressure freezing, and images suggested that the envelope of ASFV consisted of a single lipid membrane. It was less easy to interpret virus structure in chemically fixed or cryosectioned material, and in the latter case the virus envelope could be interpreted as having two membranes. Comparison of membrane widths in all three preparations indicated that the intracellular viral envelope of ASFV was not significantly different from the outer mitochondrial membrane (P < 0.05). The results support the hypothesis that the intracellular ASFV viral envelope is composed of a single lipid bilayer.
Bioimaging, Pirbright Laboratory, Institute for Animal Health, Ash Road, Pirbright, Woking, Surrey GU24 0NF, United Kingdom. pippa.hawes@bbsrc.ac.uk
Philippa C
PC
Hawes
Christopher L
CL
Netherton
Thomas E
TE
Wileman
Paul
P
Monaghan
D000358:African Swine Fever Virus / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism / Q000821:virology*; D002522:Chlorocebus aethiops; D005615:Freezing; D015686:Gene Products, env / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008854:Microscopy, Electron; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000378:metabolism / Q000821:virology*; D010455:Peptides / Q000737:chemistry; D011312:Pressure; D014709:Vero Cells; D015678:Viral Structural Proteins; D019065:Virus Assembly
D015686:Gene Products, env; D008051:Lipid Bilayers; D010455:Peptides; D015678:Viral Structural Proteins