The entry of enveloped viruses into cells begins when the membrane that surrounds these virus particles fuse with a cell membrane. The process of virus-cell fusion must be tightly regulated, to make sure it happens in the right cells. The fusion activity of measles viruses isolated from the brains of AIDS patients is not properly regulated, …
I have always had a problem with the use of the word transfection to mean anything other than the introduction of viral DNA into cells (illustrated for poliovirus). An examination of the origins of the word suggests that such use might be acceptable. The introduction of foreign DNA into cells is called DNA-mediated transformation to distinguish …
Jason Roberts, a virologist at the Victorian Infectious Disease Reference Laboratory in Melbourne, Australia, creates three-dimensional simulations of viruses showing how the molecules that make up the capsid and genome might move in very short periods of time. I visited Jason in his laboratory at the newly constructed Peter Doherty Institute, to learn how he develops …
The human prion disease, Creutzfeld-Jacob, is diagnosed by a variety of criteria, including clinical features, electroencephalograms, and magnetic resonance imaging. Until recently there was no non-invasive assay to detect PrPSc, the only specific marker for the disease. This challenge has been overcome using amplification procedures to detect Creutzfeldt-Jakob prions in nasal brushings and in urine. These …
Satellites are subviral agents that differ from viroids because they depend on the presence of a helper virus for their propagation. Satellite viruses are particles that contain nucleic acid genomes encoding a structural protein that encapsidates the satellite genome. Satellite RNAs do not encode capsid protein, but are packaged by a protein encoded in the helper virus genome. Satellite …
Genomes of non-defective viruses range in size from 2,400,000 bp of dsDNA (Pandoravirus salinus) to 1,759 bp of ssDNA (porcine circovirus). Are even smaller viral genomes possible? The subviral agents called viroids provide an answer to this question. Viroids, the smallest known pathogens, are naked, circular, single-stranded RNA molecules that do not encode protein yet replicate …
Viroids, infectious agents that encode no proteins Read More »
