Wild mouse ecotropic virus-induced spongiform encephalomyelopathy pathologically similar to scrapie was associated with the expression of retrovirus antigens in mouse brains. However, scrapie-infected mice with spongiform encephalopathy showed no increased expression of retrovirus antigens in brain. Thus, the pathogenesis of the scrapie spongiform lesion does not appear to involve activation of...

Elucidation of the immune requirements for control or elimination of retroviral infection remains an important aim. We studied the induction of adaptive immunity to neonatal infection with a murine retrovirus, under conditions leading to immunological tolerance. We found that the absence of either maternal or offspring adaptive immunity permitted efficient vertical transmission of the retroviru...

A family of dispersed, moderately repeated mouse genetic elements is expressed as retrovirus-like 30S RNA species (VL30 RNA) which can be transmitted to other cells when packaged as a pseudovirion complex by murine leukemia viruses (MuLV). Using the endogenous reverse transcriptase reaction of VL30 RNA-containing MuLV particles, full-length VL30 DNA was synthesized and cloned in pAT153. Analysi...

A porcine endogenous retrovirus (PERV) strain, PERV-A-BM, was isolated from a Bama minipig in Guangxi, China. This is the first entire genome sequence of PERV isolated from Guangxi Bama minipigs. The isolate is closely related to isolates from Wuzhishan miniature pigs and distantly related to isolates from large white pigs.

Silencing of retrovirus vectors poses a significant obstacle to genetic manipulation of stem cells and their use in gene therapy. We describe a mammalian silencer blocking assay using insulator elements positioned between retrovirus silencer elements and an LCRbeta-globin reporter transgene. In transgenic mice, we show that retrovirus silencers are blocked by the cHS4 insulator. Silencer blocki...

One obstacle to retrovirus-mediated gene therapy for human hematopoietic disorders is the low efficiency of gene transfer into pluripotent hematopoietic stem cells (HSC). We have previously shown a direct correlation between retrovirus receptor mRNA levels in mouse HSC and the efficiency with which they are transduced. In the present study, we assayed retrovirus receptor mRNA levels in a variet...

Two significant barriers limit the use of amphotropic retrovirus for human gene transfer protocols: 1) low transduction efficiency in cells with low receptor expression and 2) safety concerns originating from the risk of formation and propagation of replication competent virus in vivo. In principle, if ecotropic retrovirus, which is incapable of infecting human cells, could be transiently modif...

Studies of viruses that coevolved with lemurs provide an opportunity to understand the basal traits primate and evolutionary context for host-virus interactions. Germline integration endogenous retroviruses (ERVs) are fossil evidence past infections. Hence, characterization novel ERVs provides insight into ancient precursors extant history their hosts. Here, we report discovery a retrovirus pre...

We study the evolution of mutation rates for an asexual population living on a static fitness landscape, consisting of multiple peaks forming an evolutionary staircase. The optimal mutation rate is found by maximizing the diffusion towards higher fitness. Surprisingly the optimal genomic copying fidelity is given by Qopt = e − 1 ln ν (where ν is the genome length), independent of all other para...