Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Dependovirus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1995

Goose parvovirus--an autonomous member of the dependovirus genus?

Goose parvovirus is the etiological agent of Derzsy's disease, a fatal hepatitis of young geese. The virus infects geese and Muscovy ducks and can be propagated in the laboratory in primary embryonic goose fibroblasts. To date the virus has only been classified by morphological, biochemical, and culture characteristics as an autonomous parvovirus. We now report the cloning and partial sequencing of 3434 nucleotides of the viral genome. Three overlapping clones were obtained, encoding regions in the nonstructural and capsid coding region. The nucleotide sequence show little homology to other autonomous parvoviruses but 55% homology to the dependovirus AAV2. The homology to AAV2 was also confirmed at the amino acid level (nonstructural protein 55%, capsid coding region 51%). DNA cross hybridization studies indicate an even closer similarity of goose parvovirus to the yet unsequenced human dependoviruses AAV1 and AAV3 than to AAV2. These findings suggest that goose parvovirus may be genetically related to the dependovirus genus rather than to the other autonomous parvoviruses.

Amino Acid Sequence↗
PubMed2005

The expression strategy of goose parvovirus exhibits features of both the Dependovirus and Parvovirus genera.

The RNA transcription profile of the goose parvovirus (GPV) was determined, and it is a surprising hybrid of features of the Parvovirus and Dependovirus genera of the Parvovirinae subfamily of the Parvoviridae. Similar to the Dependovirus adeno-associated virus type 5, RNAs transcribed from the GPV upstream P9 promoter, which encode the viral nonstructural proteins, were polyadenylated at a high efficiency at a polyadenylation site [(pA)p] located within an intron in the center of the genome. Efficient usage of (pA)p required a downstream element that overlaps with the polypyrimidine tract of the A2 3' splice site of the central intron. An upstream element required for efficient use of (pA)p was also identified. RNAs transcribed from the P42 promoter, presumed to encode the viral capsid proteins, primarily extended through (pA)p and were polyadenylated at a site, (pA)d, located at the right end of the genome and ultimately spliced at a high efficiency. No promoter analogous to the Dependovirus P19 promoter was detected; however, similar to minute virus of mice and other members of the Parvovirus genus, a significant portion of pre-mRNAs generated from the P9 promoter were additionally spliced within the putative GPV Rep1 coding region and likely encode an additional, smaller, nonstructural protein. Also similar to members of the Parvovirus genus, detectable activity of the GPV P42 promoter was highly dependent on transactivation by the GPV Rep1 protein in a manner dependent on binding to a cis-element located in the P42 promoter.

Alkyl and Aryl Transferases↗
PubMed2004

A parvovirus isolated from royal python (Python regius) is a member of the genus Dependovirus.

Parvoviruses were isolated from Python regius and Boa constrictor snakes and propagated in viper heart (VH-2) and iguana heart (IgH-2) cells. The full-length genome of a snake parvovirus was cloned and both strands were sequenced. The organization of the 4432-nt-long genome was found to be typical of parvoviruses. This genome was flanked by inverted terminal repeats (ITRs) of 154 nt, containing 122 nt terminal hairpins and contained two large open reading frames, encoding the non-structural and structural proteins. Genes of this new parvovirus were most similar to those from waterfowl parvoviruses and from adeno-associated viruses (AAVs), albeit to a relatively low degree and with some organizational differences. The structure of its ITRs also closely resembled those of AAVs. Based on these data, we propose to classify this virus, the first serpentine parvovirus to be identified, as serpentine adeno-associated virus (SAAV) in the genus Dependovirus.

Amino Acid Sequence↗
PubMed1996

Coinfection of a bearded dragon, Pogona vitticeps, with adenovirus- and dependovirus-like viruses.

Four neonate bearded dragons, Pogona vitticeps, from two collections became ill and died. Multiple tissues were collected and processed for light microscopy. In hematoxylin and eosin-stained sections of liver of one lizard, numerous basophilic intranuclear inclusions were observed. In three lizards, intranuclear inclusions were primarily seen within enterocytes in the small intestine. A portion of paraffin-embedded liver of one lizard and small intestine of a second lizard were removed, deparaffinized, and examined by electron microscopy. For the most part, inclusions in the liver consisted of nonenveloped viral particles 60-66 nm in diameter. Smaller nonenveloped virions 15-17 nm in diameter were occasionally seen in association with these particles. In the intestine, inclusions consisted only of 60-70 nm particles. Based on morphology and location, the larger particles were consistent with an adenovirus. Based on size and presence within nuclei of host cells coinfected with the adenovirus-like virus, the smaller viral agent was consistent with members of the genus Dependovirus.

Adenoviridae↗
PubMed2002

An outbreak of adenoviral infection in inland bearded dragons (Pogona vitticeps) coinfected with dependovirus and coccidial protozoa (Isospora sp.).

Thirty of 200 (15%) hatchling inland bearded dragons were found dead after a short period (48 hours) of weakness and lethargy. The most common clinical signs were head tilt and circling. Six bearded dragons with neurological signs were euthanized, and postmortem examination revealed no gross abnormalities. Microscopically, severe, randomly distributed hepatocellular necrosis with large basophilic intranuclear inclusion bodies in numerous hepatocytes was noted. Small-intestinal enterocytes contained intracytoplasmic coccidial protozoa (Isospora sp.) and occasional enterocytes had basophilic intranuclear inclusion bodies. Transmission electron microscopy revealed both 80- and 20-nm-diameter viral particles, which were consistent with adenoviruses and dependoviruses, respectively. Adenoviral outbreaks in groups of animals are uncommon. An adverse synergistic effect of the coccidiosis with the adenoviral infection may have played a critical role in the high morbidity and mortality in this case.

Adenoviridae Infections↗
PubMed1995

Molecular characterization of two strains of the avian adeno-associated virus (AAAV).

An avian adeno-associated virus (AAAV) was isolated after propagating a field isolate of the CELO virus (fowl adenovirus serotype 1 (FAV1)) in embryonated eggs. The isolated dependovirus was compared with the known AAAV obtained from the American Type Culture Collection (ATCC VR-865). The genomes were analysed by digestion with several restriction endonucleases. Although both DNAs have the same size, most restriction enzymes produced different restriction patterns. Double digests were used to construct for the first time restriction maps for avian dependoviruses. The two DNAs rendered different restriction maps in which the different restriction sites were mainly located in the middle and right part of the genomes. The effect of these differences on the structure proteins was shown by western blot analysis. In the immunoblot, the immunofluorescence and immunodiffusion test the two dependoviruses were serologically indistinguishable and therefore can be regarded as two different strains of the same virus. To differentiate between both strains we named the original one as AAAV VR-865 compared with the isolated AAAV DA-1.

Animals↗
PubMed2003

Cloning of an avian adeno-associated virus (AAAV) and generation of recombinant AAAV particles.

Recent studies have proposed that adeno-associated viruses (AAVs) are not evolutionarily linked to other mammalian autonomous parvoviruses but are more closely linked to the autonomous parvoviruses of birds. To better understand the relationship between primate and avian AAVs (AAAVs), we cloned and sequenced the genome of an AAAV (ATCC VR-865) and generated recombinant AAAV particles. The genome of AAAV is 4,694 nucleotides in length and has organization similar to that of other AAVs. The entire genome of AAAV displays 56 to 65% identity at the nucleotide level with the other known AAVs. The AAAV genome has inverted terminal repeats of 142 nucleotides, with the first 122 forming the characteristic T-shaped palindromic structure. The putative Rep-binding element consists of a tandem (GAGY)(4) repeat, and the putative terminal resolution site (trs), CCGGT/CG, contains a single nucleotide substitution relative to the AAV(2) trs. The Rep open reading frame of AAAV displays 50 to 54% identity at the amino acid level with the other AAVs, with most of the diversity clustered at the carboxyl and amino termini. Comparison of the capsid proteins of AAAV and the primate dependoviruses indicate that divergent regions are localized to surface-exposed loops. Despite these sequence differences, we were able to produce recombinant AAAV particles carrying a lacZ reporter gene by cotransfection in 293T cells and were able to examine transduction efficiency in both chicken primary cells and several cell lines. Our findings indicate that AAAV is the most divergent AAV described to date but maintains all the characteristics unique to the genera of dependovirus.

Amino Acid Sequence↗
PubMed2004

Isolation of an adenovirus and an adeno-associated virus from goat kids with enteritis.

A dairy goat operation in Minnesota experienced a sudden, markedly increased mortality among its neonatal goats. Approximately 60 of 130 kids (46%) died. The animals had diarrhea and dyspnea of 1-2 days duration before death. Necropsy of 4 goat kids revealed marked, acute, catarrhal enteritis and fibrinous pleuropneumonia. Mannheimia haemolytica was isolated from the lungs. Basophilic inclusion bodies filling the entire nucleus were present in enterocytes of the ileum of 3 goats. Adenoviral particles were detected in the feces by electron microscopy and adenovirus was subsequently isolated from the intestinal content together with a parvo-like virus (dependovirus). Morphology, physicochemical characteristics, and neutralization tests indicated that the adenovirus resembled ovine adenovirus-2 (OAdV-2). However, the PstI restriction endonuclease pattern produced by the goat adenovirus was distinct from that of OAdV-2. This is the first report of enteritis in goats with an adenovirus antigenically related to OAdV-2 and with a parvo-like dependovirus.

Adenoviridae↗
PubMed1990

Parvovirus replication.

The members of the family Parvoviridae are among the smallest of the DNA viruses, with a linear single-stranded genome of about 5 kilobases. Currently the family is divided into three genera, two of which contain viruses of vertebrates and a third containing insect viruses. This review concentrates on the vertebrate viruses, with emphasis on recent advances in our insights into the molecular biology of viral replication. Traditionally the vertebrate viruses have been distinguished by the presence or absence of a requirement for a coinfection with a helper virus before productive infection can occur, hence the notion that the dependoviruses (adeno-associated viruses [AAV]) are defective. Recent data would suggest that not only is there a great deal of structural and genetic organizational similarity between the two types of vertebrate viruses, but also there is significant similarity in the molecular biology of productive replication. What differs is the physiological condition of the host cell that renders it permissive. Healthy dividing cells are permissive for productive replication by autonomous parvoviruses; such cells result in latent infection by dependoviruses. For a cell to become permissive for productive AAV replication, it must have been exposed to toxic conditions which activate a latent AAV genome. Such conditions can be caused by helper-virus infection or exposure to physical (UV light) or chemical (some carcinogens) agents. In this paper the molecular biology of replication is reviewed, with special emphasis on the role of the host and the consequences of viral infection for the host.

Animals↗
PubMed2000

The interaction of heparin sulfate and adeno-associated virus 2.

Recently heparan sulfate was proposed as the host cell receptor for the dependovirus, adeno-associated virus type 2 (AAV2). We show that although heparan sulfate on the cell surface may contribute to the binding of AAV2 to permissive cells, the amount of heparan sulfate on the cell surface as determined by flow cytometry using four different monoclonal antibodies does not correlate with AAV2 binding to cells or recombinant AAV2 transduction efficiency. Experiments with either mutant CHO cells or cells treated with chlorate to remove sulfate groups showed that sulfation was not absolutely required for infection or binding: in the absence of cell surface sulfation, recombinant AAV2 was still able to be transduced in previously permissive cells. Heparin is commonly used as a substitute in studies of the interaction between heparan sulfate and ligand, and we demonstrate that the binding affinity of AAV2/heparin is low, with a K(d) value of approximately 2.0 nM. A study of the direct interaction between AAV2 and artificial glycosaminoglycans showed that a high degree of sulfation on heparin was critical for the ability to bind AAV2 and compete rAAV2 transduction and that both O- and N-sulfate groups are required. Overall, our data suggest that, as has been shown for other viruses, the presence of a high-affinity AAV2 receptor mediates AAV2 infection in addition to the low-affinity heparan sulfate binding.

Animals↗
PubMed1988

Avian adeno-associated parvovirus and Marek's disease virus: studies of viral interactions in chicken embryo fibroblasts. Brief report.

Using growth kinetics we demonstrate two effects based on interactions between the chicken herpesvirus, Marek's disease virus (MDV), and the dependovirus, avian adeno-associated virus (AAAV), in coinfected chicken embryo fibroblasts (CEF): (i) MDV provides helper activity for an efficient multiplication of AAAV; (ii) a high multiplicity of coinfecting AAAV inhibits completely the growth of MDV as well as AAAV.

Animals↗
PubMed1989

Organization of adeno-associated virus DNA in latently infected Detroit 6 cells.

The DNA of a human dependovirus, adeno-associated virus (AAV), integrates into the cellular genome under conditions nonpermissive for viral DNA replication. The AAV DNA can be rescued from the cellular genome by superinfection with a helper virus, e.g., adenovirus. To characterize the organization of the proviral DNA in greater detail, we isolated three proviral subfragments from a latently infected human cell line. Our findings, based on sequence analysis, restriction enzyme mapping, and genomic blots, demonstrate that the viral terminal repeats (trs) are present at or near the cellular/viral DNA junctions, but significant deletions of the tr sequences have occurred. One of the proviral clones has extensive rearrangements which apparently occurred by nonhomologous recombination. The tail-to-tail arrangement of one of the proviral clones is consistent with limited DNA replication prior to integration by a mechanism similar to that seen in a productive infection. Although there are BamH1 fragments in the cell line we have characterized, which are the right size to have come from a head-to-tail tandem repeat, critical double digests show no evidence for the presence of a head-to-tail tandem repeat of wild-type proviral DNA. Use of probes derived from the flanking cellular DNA enabled us to determine that in this cell line the viral DNA had integrated into a site composed of nonrepetitive sequences.

Base Sequence↗
PubMed2005

AAV transcytosis through barrier epithelia and endothelium.

To transduce efficiently barrier epithelia such as the lung is the goal of several gene therapy applications. However, experiments with AAV-2 suggest that transduction is limited in this type of barrier epithelia. In contrast, other serotypes of AAV transduce barrier epithelia and exhibit broad dissemination throughout the tissue. Transcytosis is a process by which proteins and pathogens overcome barrier layers to reach the opposite cell surface. To understand better the entry pathway of AAV particles and their ability to penetrate barrier epithelia, we tested the hypothesis that the limited transduction of some barrier epithelia in vitro or the spread of some AAV serotypes through tissue in vivo is due to transcytosis. Our experiments demonstrate that dependoviruses can penetrate barrier cells by transcytosis. The process is rapid as well as serotype and cell-type specific and can be blocked by neutralizing antibodies, temperature, or chemical inhibitors of transcytosis. The particles isolated following apical-to-basolateral transport are still encapsulated and they can transduce permissive cell lines in vitro. Furthermore, the entry pathway used by AAV-5 for transcytosis appears to be independent of the one used for transduction. Importantly, inhibition of virus transcytosis results in a dramatic increase in intracellular vector and transduction.

Biological Transport↗
PubMed2000

Adeno-associated virus (AAV)-3-based vectors transduce haematopoietic cells not susceptible to transduction with AAV-2-based vectors.

Although adeno-associated virus (AAV)-2 has a broad tissue-host range and can transduce a wide variety of tissue types, some cells, such as erythro-megakaryoblastoid cells, are non-permissive and appear to lack the AAV-2 receptor. However, limited studies have been reported with the related dependovirus AAV-3. We have previously cloned this virus, characterized its genome and produced an infectious clone. In this study, the gene for green fluorescent protein (GFP) was inserted into AAV-2- and AAV-3-based plasmids and recombinant viruses were produced. These viruses were then used to transduce haematopoietic cells and the transduction efficiencies were compared. In contrast to recombinant (r) AAV-2, rAAV-3 successfully transduced erythroid and megakaryoblastoid cells, although rAAV-2 was superior in transduction of lymphocyte-derived cell lines. Recently, it was reported that heparan sulphate can act as a receptor of AAV-2. The infectivity of rAAV-2 and rAAV-3 was tested with mutant cell lines of Chinese hamster ovary cells that were defective for heparin or heparan sulphate expression on the cell surface. There was no correlation between the ability of rAAV-2 or rAAV-3 to infect cells and the cell surface expression of heparan sulphate and, although heparin blocked both rAAV-2 and rAAV-3 transduction, the ID(50) of rAAV-3 was higher than that of rAAV-2. In addition, virus-binding overlay assays indicated that AAV-2 and AAV-3 bound different membrane proteins. These results suggest not only that there are different cellular receptors for AAV-2 and AAV-3, but that rAAV-3 vectors may be preferred for transduction of some haematopoietic cell types.

Animals↗
PubMed1998

Adeno-associated virus Rep78 protein interacts with protein kinase A and its homolog PRKX and inhibits CREB-dependent transcriptional activation.

Adeno-associated virus (AAV) is a human parvovirus of the genus Dependovirus. AAV replication is largely restricted to cells which are coinfected with a helper virus. In the absence of a helper virus, the AAV genome can integrate into a specific chromosomal site where it remains latent until reactivated by superinfection of the host cell with an appropriate helper virus. Replication functions of AAV have been mapped to the Rep68 and Rep78 gene products. Rep proteins demonstrate DNA binding, endonuclease, and helicase activities and are involved in regulation of transcription from both AAV and heterologous promoters. AAV has been associated with suppression of oncogenicity in a range of viral and nonviral tumors. In this study we sought to identify and study cellular protein targets of AAV Rep, in order to develop a better understanding of the various activities of Rep. We used the yeast two-hybrid system to identify HeLa cell proteins that interact with AAV type 2 Rep78. We isolated several strongly interacting clones which were subsequently identified as PRKX (previously named PKX1), a recently described homolog of the protein kinase A (PKA) catalytic subunit (PKAc). The interaction was confirmed in vitro by using pMal-Rep pull-down assays. The region of Rep78 which interacts was mapped to a C-terminal zinc finger-like domain; Rep68, which lacks this domain, did not interact with PRKX. PRKX demonstrated autophosphorylation and kinase activity towards histone H1 and a PKA oligopeptide target. Autophosphorylation was inhibited by interaction with Rep78. In transfection assays, a PRKX expression vector was shown to be capable of activating CREB-dependent transcription. This activation was suppressed by Rep78 but not by Rep68. Since PRKX is a close homolog of PKAc, we investigated whether Rep78 could interact directly with PKAc. pMal-Rep78 was found to associate with purified PKAc and inhibited its kinase activity. Cotransfection experiments demonstrated that Rep78 could block the activation of CREB by a PKAc expression vector. These experiments suggest that AAV may perturb normal cyclic AMP response pathways in infected cells.

Catalysis↗
PubMed1999

Cloning and characterization of adeno-associated virus type 5.

Adeno-associated virus type 5 (AAV5) is distinct from other dependovirus serotypes based on DNA hybridization and serological data. To better understand the biology of AAV5, we have cloned and sequenced its genome and generated recombinant AAV5 particles. The single-stranded DNA genome is similar in length and genetic organization to that of AAV2. The rep gene of AAV5 is 67% homologous to AAV2, with the majority of the changes occurring in the carboxyl and amino termini. This homology is much less than that observed with other reported AAV serotypes. The inverted terminal repeats (ITRs) are also unique compared to those of the other AAV serotypes. While the characteristic AAV hairpin structure and the Rep DNA binding site are retained, the consensus terminal resolution site is absent. These differences in the Rep proteins and the ITRs result in a lack of cross-complementation between AAV2 and AAV5 as measured by the production of recombinant AAV particles. Alignment of the cap open reading frame with that of the other AAV serotypes identifies both conserved and variable regions which could affect tissue tropism and particle stability. Comparison of transduction efficiencies in a variety of cells lines and a lack of inhibition by soluble heparin indicate that AAV5 may utilize a distinct mechanism of uptake compared to AAV2.

Amino Acid Sequence↗
PubMed2004

Clades of Adeno-associated viruses are widely disseminated in human tissues.

The potential for using Adeno-associated virus (AAV) as a vector for human gene therapy has stimulated interest in the Dependovirus genus. Serologic data suggest that AAV infections are prevalent in humans, although analyses of viruses and viral sequences from clinical samples are extremely limited. Molecular techniques were used in this study to successfully detect endogenous AAV sequences in 18% of all human tissues screened, with the liver and bone marrow being the most predominant sites. Sequence characterization of rescued AAV DNAs indicated a diverse array of molecular forms which segregate into clades whose members share functional and serologic similarities. One of the most predominant human clades is a hybrid of two previously described AAV serotypes, while another clade was found in humans and several species of nonhuman primates, suggesting a cross-species transmission of this virus. These data provide important information regarding the biology of parvoviruses in humans and their use as gene therapy vectors.

Animals↗
PubMed2005

Structure of adeno-associated virus type 4.

Adeno-associated virus (AAV) is a member of the Parvoviridae, belonging to the Dependovirus genus. Currently, several distinct isolates of AAV are in development for use in human gene therapy applications due to their ability to transduce different target cells. The need to manipulate AAV capsids for specific tissue delivery has generated interest in understanding their capsid structures. The structure of AAV type 4 (AAV4), one of the most antigenically distinct serotypes, was determined to 13-A resolution by cryo-electron microscopy and image reconstruction. A pseudoatomic model was built for the AAV4 capsid by use of a structure-based sequence alignment of its major capsid protein, VP3, with that of AAV2, to which AAV4 is 58% identical and constrained by its reconstructed density envelope. The model showed variations in the surface loops that may account for the differences in receptor binding and antigenicity between AAV2 and AAV4. The AAV4 capsid surface topology also shows an unpredicted structural similarity to that of Aleutian mink disease virus and human parvovirus B19, autonomous members of the genus, despite limited sequence homology.

Amino Acid Sequence↗