1) A tentative species in the genus Vesivirus causing mucosal vesiculation and persistent infection in chimpanzees. Related genetically to Vesicular exanthema of swine virus.
Primate T-lymphotropic viruses 1-3 (PTLV-
1 to -3) Species in the genus Delta-retrovirus. The viruses HTLV-1 and STLV-1 are not clustered genetically according to host species but according to geographical origin.
van Brussel M et al (1996) J Gen Virol 77, 347
primer A short RNA sequence that pairs with one strand of DNA and provides a free 3'-OH terminus at which a DNA polymerase starts DNA synthesis, or pairs with a strand of RNA and allows reverse transcriptase to start copying the RNA into DNA. Retroviruses use specific transfer RNAs to initiate reverse transcription of the genome RNA into DNA. Endogenous human retroviruses are classified according to which tRNA primer is specified in the LTR sequence of the provirus.
prion Sigla from proteinaceous and infectious particle. Term used for the pathogens which induce neurological diseases (transmissible encephalopathies) of vertebrates, e.g. scrapie disease of sheep and goats, bovine spongiform encephalopathy in cattle, and Creutzfeld-Jakob disease in humans. Prions are oligomers composed of a 27-30kDa protein, PrPsc, that has the same amino acid sequence as a normal cell protein, PrPc, which occurs in neuronal membranes. Prions are therefore isoforms of a normal protein, capable of self-replication, but they are not viruses since they do not contain nucleic acid.
Prusiner SB (1998) In Virology, vol. 1 of Topley & Wilson's Microbiology and Microbial Infections, Ninth edition, edited by BWJ Mahy and L Collier. London: Arnold, p. 805 Prusiner SB (editor) (1999) Prion biology and Diseases. Cold Spring Harbor Laboratory Monograph 38. New York: Cold Spring Harbor Laboratory Press
Safar J et al (1998) Nature, Medicine 4, 1157
prion diseases The following diseases are probably caused by prions:
bovine spongiform encephalopathy (cattle) chronic wasting disease (mule deer and elk) Creutzfeld-Jakob disease (CJD) (humans) exotic ungulate encephalopathy (nyala and kudu)
fatal familial insomnia (humans)
feline spongiform encephalopathy (cats)
new variant CJD (humans)
scrapie (sheep and goats)
transmissible mink encephalopathy (mink)
There is strong evidence that the newly recognized fatal neurodegeneration known as new variant CJD is caused by the same prion strain as causes bovine spongiform encephalopathy (BSE).
Collinge J et al (1996) Nature 383, 685
Hill AF et al (1997) Nature 389,448
Scott MR et al (1999) Proc Natl Acad Sci 96,
probe A specific sequence of DNA or RNA which is labeled (e.g. with radioactivity or biotin) and used to detect complementary sequences by hybridization.
procapsid In some virus infections, a stage before virion formation. A viral capsid without nucleic acid.
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