Polio virus
| Poliovirus | |
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TEM micrograph of poliovirus virions. Scale bar, 50 nm. |
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| A type 3 poliovirus capsid coloured by chains. | |
| Virus classification | |
| Group: | Group IV ((+)ssRNA) |
| Order: | Picornavirales |
| Family: | Picornaviridae |
| Genus: | Enterovirus |
| Species: | Enterovirus C |
| Subtype | |
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Poliovirus |
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Poliovirus
Poliovirus, the causative agent of poliomyelitis (commonly known as polio), is a human enterovirus and member of the family of Picornaviridae.
Poliovirus is composed of an RNA genome and a protein capsid. The genome is a single-stranded positive-sense RNA genome that is about 7500 nucleotides long. The viral particle is about 30 nm in diameter with icosahedral symmetry. Because of its short genome and its simple composition—only RNA and a nonenveloped icosahedral protein coat that encapsulates it, poliovirus is widely regarded as the simplest significant virus.
Poliovirus was first isolated in 1909 by Karl Landsteiner and Erwin Popper. In 1981, the poliovirus genome was published by two different teams of researchers: by Vincent Racaniello and David Baltimore at MIT and by Naomi Kitamura and Eckard Wimmer at Stony Brook University. Poliovirus is one of the most well-characterized viruses, and has become a useful model system for understanding the biology of RNA viruses.
Poliovirus infects human cells by binding to an immunoglobulin-like receptor, CD155, (also known as the poliovirus receptor (PVR)) on the cell surface. Interaction of poliovirus and CD155 facilitates an irreversible conformational change of the viral particle necessary for viral entry. Attached to the host cell membrane, entry of the viral nucleic acid was thought to occur one of two ways: via the formation of a pore in the plasma membrane through which the RNA is then “injected” into the host cell cytoplasm, or that the virus is taken up by receptor-mediated endocytosis. Recent experimental evidence supports the latter hypothesis and suggests that poliovirus binds to CD155 and is taken up by endocytosis. Immediately after internalization of the particle, the viral RNA is released.
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Wikipedia