RESUMO
Endogenous retroviruses (ERVs) contribute to a range of germline, as well as somatic mutations in mammals. However, autonomous retrotransposition of potentially active elements has not been demonstrated in the rat genome. We cloned an insertion that disrupted the normal splicing of the Cntrob gene that was subsequently identified as a nonautonomous, novel endogenous retrovirus of the RnERV-K8e family. The RnERV-K8e family is closely related to the recently reported MmERV-K10c elements, but differs from the autonomous mouse MusD or IAP families. In addition, we identified a novel, unexpectedly close relative of RnERV-K8e in the mouse, suggesting ERV-K cross-species transmission between mice and rats. We cloned a potentially autonomous RnERV-K8e element identified by in silico analysis and, using an in vitro retrotransposition assay, demonstrated that it is capable of retrotransposition. This particular element (named Rat-rho, pronounced "retro") encodes a retroviral envelope gene (env); however, env is not required for de novo retrotransposition events. Significant levels of RnERV-K8e-associated genetic polymorphisms were detected among inbred rat strains, suggesting ongoing retrotransposition in the rat genome. This study identifies an ERV-K-type family in rats that shows obvious signs of recent activity. Ongoing retrotranspositional activity may significantly add to genomic variability among inbred rat strains.
Assuntos
Retrovirus Endógenos , Variação Genética , Genoma/genética , Ratos Endogâmicos/genética , Ratos Endogâmicos/virologia , Proteínas do Envelope Viral/genética , Animais , Elementos de DNA Transponíveis/genética , Retrovirus Endógenos/classificação , Retrovirus Endógenos/genética , Feminino , Genes Virais/genética , Masculino , Camundongos , Dados de Sequência Molecular , Ratos , Análise de Sequência de DNA , Especificidade da Espécie , Integração ViralRESUMO
The present study contains information about proper microbiological monitoring of laboratory animals' health and the standardization of microbiological monitoring methods in Korea. Microbiological quality control for laboratory animals, composed of biosecurity and health surveillance, is essential to guard against research complications and public health dangers that have been associated with adventitious infections. In this study, one hundred and twenty-two mice and ninety rats from laboratory animal breeding companies and one animal facility of the national universities in Korea were monitored in 2000-2003. Histopathologically, thickening of the alveolar walls and lymphocytic infiltration around the bronchioles were observed in mice and rats from microbiologically contaminated facilities. Cryptosporidial oocysts were observed in the gastric pits of only conventionally-housed mice and rats. Helicobacter spp. infection was also detected in 1 of 24 feces DNA samples in mice and 9 of 40 feces DNA samples in rats by PCR in 2003, but they were not Helicobacter hepaticus. This paper describes bacteriological, parasitological, and virological examinations of the animals.
Assuntos
Animais de Laboratório/microbiologia , Camundongos Endogâmicos/microbiologia , Ratos Endogâmicos/microbiologia , Organismos Livres de Patógenos Específicos , Animais , Animais de Laboratório/parasitologia , Animais de Laboratório/virologia , Cryptosporidium/isolamento & purificação , Ensaio de Imunoadsorção Enzimática , Helicobacter/isolamento & purificação , Abrigo para Animais , Coreia (Geográfico) , Camundongos , Camundongos Endogâmicos/parasitologia , Camundongos Endogâmicos/virologia , Vírus da Hepatite Murina/isolamento & purificação , Mycoplasma/isolamento & purificação , Reação em Cadeia da Polimerase , Quarentena/normas , Ratos , Ratos Endogâmicos/parasitologia , Ratos Endogâmicos/virologia , Vírus Sendai/isolamento & purificaçãoRESUMO
Two virus strains were isolated from the lungs of athymic rats and mice used as sentinel animals in 2 colonies of laboratory rats in Japan in which antibodies to the pneumonia virus of mice (PVM) had been detected. The new isolates were identified as PVM by the following characteristics: RNA virus, susceptibility to ether treatment, long filamentous viral structure in the cytoplasm of infected cells, and hemagglutinating activity in various erythrocytes, including those of mice and rats. In addition, cross neutralization with the prototype of PVM (No. 15 strain) was observed. This is the first report of the isolation of PVM from laboratory animals in Japan.
