Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The results are presented of a special study to determine whether variola-like "whitepox" viruses could arise as white pock variants of monkeypox virus after one or a few mutations. DNA mapping by cross-hybridization of restriction endonuclease DNA fragments was carried out on 18 orthopoxviruses relevant to this study, including variola and monkeypox viruses and white (non-haemorrhagic) pock producers recovered from chorioallantoic membranes infected with red (haemorrhagic) pock-producing monkeypox viruses. The distinctiveness of the DNA maps of true variola and monkeypox viruses indicated that spontaneous production of "whitepox" from monkeypox virus was genetically impossible. These and other observations led to the conclusion that the "whitepox" viruses recovered from monkeypox virus stocks had an exogenous origin.
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PMID:Can variola-like viruses be derived from monkeypox virus? An investigation based on DNA mapping. 300 51

Monkeypox mutants arising spontaneously or after serial, high multiplicity passage were characterized phenotypically and by restriction endonuclease mapping. Some resemble "whitepox" and variola viruses in several of the markers tested but all are distinguishable phenotypically from these. None resembles "whitepox" viruses in genome structure although near-terminal deletions or symmetrical, terminal rearrangements, relative to parental monkeypox, occurred. "Whitepox" viruses isolated from animals closely resemble variola in both phenotype and genome structure.
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PMID:Comparison of white pock (h) mutants of monkeypox virus with parental monkeypox and with variola-like viruses isolated from animals. 624 94

DNA from isolates of monkeypox virus, when digested with the endonuclease PstI, gave fragment-size profiles which correlated with the geographic area from which the isolate originated. Although some of the differences were located subterminally in the genome, others mapped to the central conserved region. Further differentiation of the viral genomes was sought by analysis of a short region within the central conserved part of the genome that appeared to be a partially deleted counterpart of an intact 1024 bp open reading frame (ORF) present in variola and vaccinia virus genomes. We reasoned that this region would not be conserved by functional selection and would therefore be likely to show more variation between isolates of monkeypox virus. The deletions found in monkeypox virus isolates from Liberia and from Benin were almost the same as that which we had previously found in the Denmark strain. A much shortened ORF, potentially coding for a product of 133 amino acids, was retained in all three West African isolates, but three Zairean isolates each showed an identical series of small insertions and deletions which effectively abolish the ORF. Three deletions, present in all isolates, must pre-date the geographical separation of monkeypox virus lineages; other, presumably more recent, changes differ between the Zairean and West African isolates. In contrast, the base similarity was found to be more than 99% when all the monkeypox virus sequences were appropriately aligned. This, in a disrupted and presumably nonfunctional gene also indicates that the changes described are recent. It is suggested that insertions and deletions occur regularly during poxvirus DNA replication, but are preserved only in sequences that are not required for continued transmission in the natural host.
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PMID:Evidence for recent genetic variation in monkeypox viruses. 820 96

A variant of variola virus is described which produces a late polypeptide of 25 kDa instead of one of 27 kDa and which has an additional endonuclease cleavage site for SalI in the viral DNA. These markers were shown to be genetically independent and to characterize 14 of the 48 variola strains which were examined. The variant strains were isolated from smallpox outbreaks originating in or from Pakistan between 1961 and 1974 and also from two cases at a Mission Hospital in Vellore, India in 1964. No variant strains were found among 9 other isolates from cases of variola major occurring in other parts of India or in Bangladesh, nor among 4 isolates from Indonesia, 15 from Africa or 6 isolates of variola minor.
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PMID:A variant of variola virus, characterized by changes in polypeptide and endonuclease profiles. 1035 94