Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2000-5-16
pubmed:abstractText
The early stages of Venezuelan equine encephalitis virus (VEE) pathogenesis in the mouse model have been examined using a genetic approach. Disease progression of a molecularly cloned single-site mutant was compared with that of the parental virus to determine the step in the VEE pathogenetic sequence at which the mutant was blocked. Assuming that such a block constitutes a genetic screen, isolates from different tissues thought to be distal to the block in the VEE pathogenetic sequence were analyzed to determine the pathogenetic step at which revertants of the mutant were selected. Directed mutation and analysis of reversion in vivo provide two powerful genetic tools for the dissection of the wild-type VEE pathogenetic sequence. Virus from the parental virulent clone, V3000, first replicated in the draining lymph node after subcutaneous inoculation in the left rear footpad. Movement of a cloned avirulent mutant, V3010 (E2 76 Glu to Lys), to the draining lymph node was impaired, replication in the node was delayed, and spread beyond the draining lymph node was sporadic. Serum, contralateral lymph node, spleen, and brain isolates from V3010 inoculated animals were invariably revertant with respect to sequence at E2 76 and/or virulence in mice. Revertants isolated from serum and contralateral lymph node retained the V3010 E2 Lys 76 mutation but also contained a second-site mutation, Glu to Lys at E2 116. Modification of the V3010 clone by addition of the second-site mutation at E2 116 produced a virus that bypassed the V3010 block at the draining lymph node but that did not possess full wild-type capacity for replication in the central nervous system or for induction of mortality. A control construct containing only the E2 116 reverting mutation on the V3000 background was identical to V3000 in terms of early pathogenetic steps and virulence. Therefore, analysis of mutant replication and reversion in vivo suggested (1) that the earliest steps in VEE pathogenesis are transit to the draining lymph node and replication at that site, (2) that the mutation in V3010 impairs transit to the draining lymph node and blocks dissemination to other tissues, and (3) that reversion can overcome the block without restoring full virulence.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0042-6822
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Academic Press.
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
270
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
111-23
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:10772984-Animals, pubmed-meshheading:10772984-Brain, pubmed-meshheading:10772984-Cell Line, pubmed-meshheading:10772984-Cloning, Molecular, pubmed-meshheading:10772984-Disease Progression, pubmed-meshheading:10772984-Encephalitis Virus, Venezuelan Equine, pubmed-meshheading:10772984-Encephalomyelitis, Venezuelan Equine, pubmed-meshheading:10772984-Female, pubmed-meshheading:10772984-Lymph Nodes, pubmed-meshheading:10772984-Mice, pubmed-meshheading:10772984-Phenotype, pubmed-meshheading:10772984-Point Mutation, pubmed-meshheading:10772984-RNA, Viral, pubmed-meshheading:10772984-Spleen, pubmed-meshheading:10772984-Structure-Activity Relationship, pubmed-meshheading:10772984-Suppression, Genetic, pubmed-meshheading:10772984-Vaccines, Attenuated, pubmed-meshheading:10772984-Viral Envelope Proteins, pubmed-meshheading:10772984-Viral Vaccines, pubmed-meshheading:10772984-Viremia, pubmed-meshheading:10772984-Virulence, pubmed-meshheading:10772984-Virus Replication
pubmed:year
2000
pubmed:articleTitle
A single-site mutant and revertants arising in vivo define early steps in the pathogenesis of Venezuelan equine encephalitis virus.
pubmed:affiliation
Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7290, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.