scholarly journals The Nucleotide Sequence of Koala (Phascolarctos cinereus) Retrovirus: a Novel Type C Endogenous Virus Related to Gibbon Ape Leukemia Virus

2000 ◽  
Vol 74 (9) ◽  
pp. 4264-4272 ◽  
Author(s):  
Jon J. Hanger ◽  
Lindell D. Bromham ◽  
Jeff J. McKee ◽  
Tracy M. O'Brien ◽  
Wayne F. Robinson
Keyword(s):  
Reverse Transcriptase ◽  
Genomic Dna ◽  
Leukemia Virus ◽  
Endogenous Retrovirus ◽  
Reverse Transcriptase Activity ◽  
Endogenous Virus ◽  
Peripheral Blood Mononuclear ◽  
Phascolarctos Cinereus ◽  
Clinically Normal ◽  
Gibbon Ape Leukemia Virus

ABSTRACT A novel retrovirus, morphologically consistent with mammalian C-type retroviruses, was detected by electron microscopy in mitogen-stimulated peripheral blood mononuclear cell cultures from 163 koalas and in lymphoma tissue from 3 koalas. PCR amplified provirus from the blood and tissues of 17 wild and captive koalas, and reverse transcriptase-PCR demonstrated viral mRNA, viral genomic RNA, and reverse transcriptase activity in koala serum and cell culture supernatants. Comparison of viral sequences derived from genomic DNA and mRNA showed identity indicative of a single retroviral species—here designated koala retrovirus (KoRV). Southern blot analysis of koala tissue genomic DNA using labelled KoRV probes demonstrated banding consistent with an endogenous retrovirus. Complete and apparently truncated proviruses were detected in DNA of both clinically normal koalas and those with hematopoietic disease. KoRV-related viruses were not detected in other marsupials, and phylogenetic analysis showed that KoRV paradoxically clusters with gibbon ape leukemia virus (GALV). The strong similarity between GALV and KoRV suggests that these viruses are closely related and that recent cross-host transmission has occurred. The complete proviral DNA sequence of KoRV is reported.

scholarly journals Gammaretrovirus-Specific Antibodies in Free-Ranging and Captive Namibian Cheetahs

2015 ◽  
Vol 22 (6) ◽  
pp. 611-617 ◽  
Author(s):  
Annika Krengel ◽  
Valentino Cattori ◽  
Marina L. Meli ◽  
Bettina Wachter ◽  
Jürg Böni ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Real Time ◽  
Real Time Pcr ◽  
Mononuclear Cells ◽  
Leukemia Virus ◽  
Reverse Transcriptase Activity ◽  
Feline Leukemia Virus ◽  
Quantitative Real Time Pcr ◽  
Peripheral Blood Mononuclear ◽  
Free Ranging

ABSTRACTThe cheetah population in Namibia is the largest free-ranging population in the world and a key population for research regarding the health status of this species. We used serological methods and quantitative real-time PCR to test free-ranging and captive Namibian cheetahs for the presence of feline leukemia virus (FeLV), a gammaretrovirus that can be highly aggressive in populations with low genetic diversity, such as cheetahs. We also assessed the presence of antibodies to other gammaretroviruses and the responses to a FeLV vaccine developed for domestic cats. Up to 19% of the free-ranging cheetahs, 27% of the captive nonvaccinated cheetahs, and 86% of the captive vaccinated cheetahs tested positive for FeLV antibodies. FeLV-antibody-positive free-ranging cheetahs also tested positive for Rauscher murine leukemia virus antibodies. Nevertheless, FeLV was not detectable by quantitative real-time PCR and no reverse transcriptase activity was detectable by product-enhanced reverse transcriptase assay in the plasma of cheetahs or the supernatants from cultures of peripheral blood mononuclear cells. The presence of antibodies to gammaretroviruses in clinically healthy specimens may be caused either by infection with a low-pathogenic retrovirus or by the expression of endogenous retroviral sequences. The strong humoral immune responses to FeLV vaccination demonstrate that cheetahs can respond to the vaccine and that vaccination against FeLV infection may be beneficial should FeLV infection ever become a threat, as was seen in Iberian lynx and Florida panthers.

scholarly journals Ribozyme cleaves rex/tax mRNA and inhibits bovine leukemia virus expression

1993 ◽  
Vol 90 (23) ◽  
pp. 10932-10936 ◽  
Author(s):  
G H Cantor ◽  
T F McElwain ◽  
T A Birkebak ◽  
G H Palmer
Keyword(s):  
Reverse Transcriptase ◽  
Bovine Leukemia Virus ◽  
Core Protein ◽  
Leukemia Virus ◽  
Reverse Transcriptase Activity ◽  
Regulatory Proteins ◽  
Dna Encoding ◽  
Free System ◽  
Synthetic Dna ◽  
Virus Expression

Bovine leukemia virus (BLV) encodes at least two regulatory proteins, Rex and Tax. Tax, the transactivating protein, stimulates the long terminal repeat to promote viral transcription and may be involved in tumorigenesis. Rex is involved in the transition from early expression of regulatory proteins to later expression of viral structural proteins. We have targeted ribozymes against the mRNA encoding Rex and Tax. The ribozymes consist of the hammer-head catalytic motif flanked by antisense sequences that hybridize with the complementary rex/tax mRNA. To evaluate cleavage in a cell-free system, we transcribed portions of rex/tax mRNA and incubated them with synthetic RNA ribozymes. A ribozyme was identified that cleaves > 80% of the target RNA. Synthetic DNA encoding this ribozyme was cloned into the expression vector pRc/RSV and transfected into BLV-infected bat lung cells. Intracellular cleavage of rex/tax mRNA was confirmed by reverse transcriptase PCR. In cells expressing the ribozyme, viral expression was markedly inhibited. Expression of the BLV core protein p24 was inhibited by 61%, and reverse transcriptase activity in supernatant was inhibited by 92%. Ribozyme inhibition of BLV expression suggests that cattle expressing these sequences may be able to control BLV replication.

scholarly journals In Vitro Interactions between Apricitabine and Other Deoxycytidine Analogues

2007 ◽  
Vol 51 (8) ◽  
pp. 2948-2953 ◽  
Author(s):  
R. Bethell ◽  
J. De Muys ◽  
J. Lippens ◽  
A. Richard ◽  
B. Hamelin ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
High Performance ◽  
Mononuclear Cells ◽  
Human Peripheral Blood ◽  
Transcriptase Inhibitor ◽  
Reverse Transcriptase Activity ◽  
Peripheral Blood Mononuclear ◽  
Reverse Transcriptase Inhibitor ◽  
Hiv 1

ABSTRACT Apricitabine is a novel deoxycytidine analogue reverse transcriptase inhibitor that is under development for the treatment of human immunodeficiency virus type 1 (HIV-1) infection. Apricitabine is phosphorylated to its active triphosphate by deoxycytidine kinase, which is also responsible for the intracellular phosphorylation of lamivudine (3TC) and emtricitabine (FTC); hence, in vitro studies were performed to investigate possible interactions between apricitabine and these agents. Human peripheral blood mononuclear cells (PBMC) were incubated for 24 h with various concentrations of 3H-labeled or unlabeled apricitabine, 3TC, or FTC. Intracellular concentrations of parent compounds and their phosphorylated derivatives were measured by high-performance liquid chromatography. In other experiments, viral reverse transcriptase activity was measured in PBMC infected with HIV-1 bearing M184V in the presence of various concentrations of apricitabine and 3TC. [3H]apricitabine and [3H]3TC were metabolized intracellularly to form mono-, di-, and triphosphates. 3TC and FTC (1 to 10 μM) produced concentration-dependent decreases in apricitabine phosphorylation; in contrast, apricitabine at concentrations of up to 30 μM had no effect on the phosphorylation of 3TC or FTC. The combination of apricitabine and 3TC reduced the antiviral activity of apricitabine against HIV-1: apricitabine concentrations producing 50% inhibition of viral reverse transcriptase were increased two- to fivefold in the presence of 3TC. These findings suggest that nucleoside reverse transcriptase inhibitors with similar modes of action may show biochemical interactions that affect their antiviral efficacy. It is therefore essential that potential interactions between combinations of new and existing agents be thoroughly investigated before such combinations are introduced into clinical practice.

scholarly journals Identification of diverse groups of endogenous gammaretroviruses in mega- and microbats

2012 ◽  
Vol 93 (9) ◽  
pp. 2037-2045 ◽  
Author(s):  
Jie Cui ◽  
Gilda Tachedjian ◽  
Mary Tachedjian ◽  
Edward C. Holmes ◽  
Shuyi Zhang ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Leukemia Virus ◽  
Large Deletion ◽  
Endogenous Retroviruses ◽  
Myotis Lucifugus ◽  
Phylogenetic Study ◽  
Endogenous Virus ◽  
Pteropus Vampyrus ◽  
Gibbon Ape Leukemia Virus ◽  
Diverse Groups

A previous phylogenetic study suggested that mammalian gammaretroviruses may have originated in bats. Here we report the discovery of RNA transcripts from two putative endogenous gammaretroviruses in frugivorous (Rousettus leschenaultii retrovirus, RlRV) and insectivorous (Megaderma lyra retrovirus, MlRV) bat species. Both genomes possess a large deletion in pol, indicating that they are defective retroviruses. Phylogenetic analysis places RlRV and MlRV within the diversity of mammalian gammaretroviruses, with the former falling closer to porcine endogenous retroviruses and the latter to Mus dunni endogenous virus, koala retrovirus and gibbon ape leukemia virus. Additional genomic mining suggests that both microbat (Myotis lucifugus) and megabat (Pteropus vampyrus) genomes harbour many copies of endogenous retroviral forms related to RlRV and MlRV. Furthermore, phylogenetic analysis reveals the presence of three genetically diverse groups of endogenous gammaretroviruses in bat genomes, with M. lucifugus possessing members of all three groups. Taken together, this study indicates that bats harbour distinct gammaretroviruses and may have played an important role as reservoir hosts during the diversification of mammalian gammaretroviruses.

scholarly journals Infectious KoRV-related retroviruses circulating in Australian bats

2020 ◽  
Vol 117 (17) ◽  
pp. 9529-9536 ◽  
Author(s):  
Joshua A. Hayward ◽  
Mary Tachedjian ◽  
Claudia Kohl ◽  
Adam Johnson ◽  
Megan Dearnley ◽  
...  
Keyword(s):  
Leukemia Virus ◽  
Reverse Transcriptase Activity ◽  
Close Relative ◽  
Emerging Viruses ◽  
Basal Group ◽  
Serologic Evidence ◽  
Mouse Cells ◽  
Gibbon Ape Leukemia Virus

Bats are reservoirs of emerging viruses that are highly pathogenic to other mammals, including humans. Despite the diversity and abundance of bat viruses, to date they have not been shown to harbor exogenous retroviruses. Here we report the discovery and characterization of a group of koala retrovirus-related (KoRV-related) gammaretroviruses in Australian and Asian bats. These include the Hervey pteropid gammaretrovirus (HPG), identified in the scat of the Australian black flying fox (Pteropus alecto), which is the first reproduction-competent retrovirus found in bats. HPG is a close relative of KoRV and the gibbon ape leukemia virus (GALV), with virion morphology and Mn2+-dependent virion-associated reverse transcriptase activity typical of a gammaretrovirus. In vitro, HPG is capable of infecting bat and human cells, but not mouse cells, and displays a similar pattern of cell tropism as KoRV-A and GALV. Population studies reveal the presence of HPG and KoRV-related sequences in several locations across northeast Australia, as well as serologic evidence for HPG in multiple pteropid bat species, while phylogenetic analysis places these bat viruses as the basal group within the KoRV-related retroviruses. Taken together, these results reveal bats to be important reservoirs of exogenous KoRV-related gammaretroviruses.

Sign in / Sign up

Export Citation Format

Share Document