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PubMed1994

Characterization of the feline host range and a specific epitope of feline panleukopenia virus.

The feline parvovirus subgroup is comprised of viruses isolated from various carnivores, including the dog, cat, mink, raccoon, Arctic fox, and raccoon dog. Those viruses are > 98% identical in their DNA sequences and are very similar antigenically. We have shown that although canine parvovirus (CPV) replicates in numerous feline cell lines in vitro it does not infect cats after parenteral inoculation (U. Truyen and C. R. Parrish, (1992) J. Virol. 66, 5399-5408). Here we use recombination mapping to locate some viral determinants required for feline host range, and show that the ability to replicate in cats was determined by the right-hand 45% of the genome, most likely a function of the capsid protein gene. Efficient replication in the cat appeared to require feline panleukopenia virus sequences from both ends of the VP2 molecule, which contained differences of VP2 amino acid residues 80, 564, and 568. The difference at amino acid 80 was also associated with expression of an FPV-specific antigenic epitope. The differences which affected the feline host range were located in a region of the capsid structure where three VP2 molecules interact, and the mutations gave rise to changes in the conformation of loops of the three adjoining VP2 monomers. The mechanism(s) of the in vivo feline host range restriction were not defined, and we were unable to show in vitro inhibition of virus infectivity by feline serum components or erythrocytes.

Animals↗

PubMed2006

M-T5, the ankyrin repeat, host range protein of myxoma virus, activates Akt and can be functionally replaced by cellular PIKE-A.

The myxoma virus (MV) ankyrin repeat, host range factor M-T5 has the ability to bind and activate cellular Akt, leading to permissive MV replication in a variety of diverse human cancer cell lines (G. Wang, J. W. Barrett, M. Stanford, S. J. Werden, J. B. Johnston, X. Gao, M. Sun, J. Q. Cheng, and G. McFadden, Proc. Natl. Acad. Sci. USA 103:4640-4645, 2006). The susceptibility of permissive human cancer cells to MV infection is directly correlated with the basal or induced levels of phosphorylated Akt. When M-T5 is deleted from MV, the knockout virus, vMyxT5KO, can no longer productively infect a subset of human cancer cells (designated type II) that exhibit little or no endogenous phosphorylated Akt. In searching for a host counterpart of M-T5, we noted sequence similarity of M-T5 to a recently identified ankyrin repeat cellular binding protein of Akt called PIKE-A. PIKE-A binds and activates the kinase activity of Akt in a GTP-dependent manner and promotes the invasiveness of human cancer cell lines. Here, we demonstrate that transfected PIKE-A is able to rescue the ability of vMyxT5KO to productively infect type II human cancer cells that were previously resistant to infection. Also, cancer cells that were completely nonpermissive for both wild-type and vMyxT5KO infection (called type III) were rendered fully permissive following ectopic expression of PIKE-A. We conclude that the MV M-T5 host range protein is functionally interchangeable with the host PIKE-A protein and that the activation of host Akt by either M-T5 or PIKE-A is critical for the permissiveness of human cancer cells for MV.

Amino Acid Sequence↗

PubMed2003

Determinants of the host range restriction of replication of bovine parainfluenza virus type 3 in rhesus monkeys are polygenic.

The Kansas strain of bovine parainfluenza virus type 3 (BPIV3) is 100- to 1,000-fold restricted in replication in the respiratory tracts of nonhuman primates compared to human PIV3 (HPIV3), an important pathogen of infants and young children. BPIV3 is also restricted in replication in human infants and children, yet it is immunogenic and is currently being evaluated in clinical trials as a vaccine candidate to protect against illness caused by HPIV3. We have examined the genetic basis for the host range attenuation phenotype of BPIV3 by exchanging each open reading frame (ORF) of a recombinant wild-type HPIV3 with the analogous ORF from BPIV3, with the caveats that the multiple ORFs of the P gene were exchanged as a single unit and that the HN and F genes were exchanged as a single unit. Recombinant chimeric bovine-human PIV3s were recovered from cDNA, and the levels of viral replication in vitro and in the respiratory tract of rhesus monkeys were determined. Recombinant chimeric HPIV3s bearing the BPIV3 N or P ORF were highly attenuated in the upper and lower respiratory tracts of monkeys, whereas those bearing the BPIV3 M or L ORF or the F and HN genes were only moderately attenuated. This indicates that the genetic determinants of the host range restriction of replication of BPIV3 for primates are polygenic, with the major determinants being the N and P ORFs. Monkeys immunized with these bovine-human chimeric viruses, including the more highly attenuated ones, developed higher levels of HPIV3 hemagglutination-inhibiting serum antibodies than did monkeys immunized with BPIV3 and were protected from challenge with wild-type HPIV3. Furthermore, host range determinants could be combined with attenuating point mutations to achieve an increased level of attenuation. Thus, chimeric recombinant bovine-human PIV3 viruses that manifest different levels of attenuation in rhesus monkeys are available for evaluation as vaccine candidates to protect infants from the severe lower respiratory tract disease caused by HPIV3.

Animals↗

PubMed2003

Morphological, host range, and genetic characterization of two coliphages.

Two coliphages, AR1 and LG1, were characterized based on their morphological, host range, and genetic properties. Transmission electron microscopy showed that both phages belonged to the Myoviridae; phage particles of LG1 were smaller than those of AR1 and had an isometric head 68 nm in diameter and a complex contractile tail 111 nm in length. Transmission electron micrographs of AR1 showed phage particles consisting of an elongated isometric head of 103 by 74 nm and a complex contractile tail 116 nm in length. Both phages were extensively tested on many strains of Escherichia coli and other enterobacteria. The results showed that both phages could infect many serotypes of E. coli. Among the enterobacteria, Proteus mirabilis, Shigella dysenteriae, and two Salmonella strains were lysed by the phages. The genetic material of AR1 and LG1 was characterized. Phage LG1 had a genome size of 49.5 kb compared to 150 kb for AR1. Restriction endonuclease analysis showed that several restriction enzymes could degrade DNA from both phages. The morphological, genome size, and restriction endonuclease similarities between AR1 and phage T4 were striking. Southern hybridizations showed that AR1 and T4 are genetically related. The wide host ranges of phages AR1 and LG1 suggest that they may be useful as biocontrol, therapeutic, or diagnostic agents to control and detect the prevalence of E. coli in animals and food.

Bacteria↗

PubMed2002

The complete nucleotide sequence and environmental distribution of the cryptic, conjugative, broad-host-range plasmid pIPO2 isolated from bacteria of the wheat rhizosphere.

Plasmid pIPO2 is a cryptic, conjugative, broad-host-range plasmid isolated from the wheat rhizosphere. It efficiently self-transfers between alpha, beta and gamma Proteobacteria and has a mobilizing/retromobilizing capacity for IncQ plasmids. The complete nucleotide sequence of pIPO2 is presented on the basis of its mini-Tn5::luxABtet-tagged derivative, pIPO2T. The pIPO2 sequence is 39815 bp long and contains at least 43 complete ORFs. Apart from a suite of ORFs with unknown function, all of the genes carried on pIPO2 are predicted to be involved in plasmid replication, maintenance and conjugative transfer. The overall organization of these genes is different from previously described plasmids, but is similar to the genetic organization seen in pSB102, a conjugative plasmid recently isolated from the bacterial community of the alfalfa rhizosphere. The putative conjugative transfer region of pIPO2 covers 23 kb and contains the genes required for DNA processing (Dtr) and mating pair formation (Mpf). The organization of these transfer genes in pIPO2 is highly similar to the genetic organization seen in the environmental plasmid pSB102 and in pXF51 from the plant pathogen Xylella fastidiosa. Plasmids pSB102 and pXF51 have recently been proposed to form a new family of environmental broad-host-range plasmids. Here it is suggested that pIPO2 is a new member of this family. The proposed Mpf system of pIPO2 shares high amino acid sequence similarity with equivalent VirB proteins from the type IV secretion system of Brucella spp. Sequence information was used to design primers specific for the detection of pIPO2. Environmental DNA from a range of diverse habitats was screened by PCR with these primers. Consistently positive signals for the presence of pIPO2 were obtained from a range of soil-related habitats, including the rhizospheres of young wheat plants, of field-grown oats and of grass (all gramineous plants), as well as from the rhizosphere of tomato plants. These data add to the growing evidence that plasmids carry advantageous genes with as yet undefined functions in plant-associated communities.

Amino Acid Motifs↗

PubMed2004

Transmission cycles, host range, evolution and emergence of arboviral disease.

Many pandemics have been attributed to the ability of some RNA viruses to change their host range to include humans. Here, we review the mechanisms of disease emergence that are related to the host-range specificity of selected mosquito-borne alphaviruses and flaviviruses. We discuss viruses of medical importance, including Venezuelan equine and Japanese encephalitis viruses, dengue viruses and West Nile viruses.

Alphavirus↗

PubMed1998

Molecular evolution of a host-range gene in geminiviruses infecting asexual populations of Eupatorium makinoi.

Asexual plants of Eupatorium makinoi is frequently infected with tobacco leaf curl geminivirus (TLCV). The host range of TLCV is narrow, and ORF C4 is considered to function as a host range determinant. Using this TLCV-Eupatorium system, we tested the expectation that the rate of amino acid replacements will be accelerated in ORF C4 if resistant genes of the host plants drive molecular evolution in ORF C4. ORF C4 is entirely contained within a longer ORF C1 encoding a replication protein. We analyzed 21 sequences containing ORF C4 and a part of ORF C1. While per-site number of synonymous substitutions exceeded that of replacements in ORF C1, per-site number of replacements exceeded that of synonymous substitutions in ORF C4. However, this excess of per-site replacement in ORF C4 was mostly explained by the overlap gene nature, because most synonymous substitutions in ORF C1 change amino acid of ORF C4. In conclusion, not positive but negative selection is a predominant mode characterizing molecular evolution of ORF C4.

Asteraceae↗

PubMed1987

The early enhancer-promoter of BKV and host range for transformation.

The early genes of the human papovavirus BKV and simian virus 40 (SV40) show a different host range for transformation. The early region of SV40 efficiently transforms human fibroblast cells, whereas the early region of BKV does not. Interchanging noncoding enhancer-promoter sequences around the origin of replication between BKV and SV40 showed that the early enhancer-promoter sequences of BKV and SV40 could substitute for each other, as far as the induction of expression of tumor antigens and morphological transformation is concerned; the efficiency of transformation was influenced by the enhancer-promoter sequences, and the difference in host range for transformation between BKV and SV40 was determined by the early gene products rather than by the enhancer-promoter sequences.

Animals↗

PubMed1996

DNA replication of IncQ broad-host-range plasmids in gram-negative bacteria.

Bacterial plasmids of Escherichia coli incompatibility group Q (IncQ) are broad-host-range plasmids that are able to proliferate in almost all Gram-negative bacteria. They are small, nonconjugative, and multicopy plasmids. They can be mobilized into many species of Gram-negative bacteria by coresident conjugative plasmids. Plasmids RSF1010, R1162, and R300B have DNAs of a size of 8.7 kb, and are best studied among IncQ plasmids. These plasmids encode by themselves three major proteins essential for the initiation of DNA replication. This makes the plasmid DNA replication less dependent on the DNA replication apparatus of host cells, and leads to promiscuity or a broad host range. Considering the biological features of these plasmids, they are potent DNA cloning vehicles. Moreover, their characteristic DNA replication mechanism that makes IncQ plasmids promiscuous is elaborate, and is an interesting object of scientific studies.

DNA Replication↗

PubMed1991

Host range expansion by recombination of the baculoviruses Bombyx mori nuclear polyhedrosis virus and Autographa californica nuclear polyhedrosis virus.

The mechanisms of host specificity of nuclear polyhedrosis viruses (NPVs) (Baculoviridae) were analyzed after coinfection of Bombyx mori NPV (BmNPV) and one of four distinct groups of Spodoptera litura NPV (SlNPV), including an Autographa californica NPV (AcNPV) variant (S. Maeda, Y. Mukohara, and A. Kondo, J. Gen. Virol. 71:2631-2639, 1990), into various lepidopteran cell lines. Replication of BmNPV in nonpermissive cells (TN-386, SF-21, and CLS-79) was induced by coinfection with AcNPV but not with the other three SlNPV groups. These induced progeny NPVs were plaque purified in BmN cells, which are susceptible to only BmNPV, and characterized. Most of these isolates did not replicate in the cell lines in which they were produced, indicating the existence of a helper function of AcNPV for BmNPV replication in nonpermissive cells. Some of these isolates, however, were able to replicate in cell lines nonpermissive to BmNPV, indicating the appearance of a new virus with wider host specificity. DNA restriction endonuclease analysis showed that the isolates exhibiting wider host range were recombinant viruses between the parents, AcNPV and BmNPV, resulting from various types of crossovers of relatively large areas of their genomes. Expansion of host range was also observed in larvae.

Animals↗

PubMed1986

env genes of avian retroviruses: nucleotide sequence and molecular recombinants define host range determinants.

The env gene of avian sarcoma and leukosis retroviruses is allelic in the virus population permitting the virus to use different host cell receptors. This polymorphism has allowed the classification of these viruses into different subgroups. In order to understand further the role of viral sequences involved in determining this host range phenomenon, we constructed molecular recombinants between subgroup A, B, and E viruses and showed that the host range determinant defining subgroup specificity was located within a 1.1-kb region of the genome that included most of the coding region for the env gene product gp85. We also determined the nucleotide sequence of the region of the env gene encoding gp85 for virus isolates representing subgroup A and B viruses. We compared the predicted amino acid sequences of gp85 to themselves and to the previously published sequences of subgroup B, C, and E env genes. Based on these comparisons, we draw the following conclusions: Within the gp85 coding domain, there are four variable regions (VR-1 to VR-4) ranging in size from 9 to 52 amino acids. The variable regions are located in the same relative positions for each of the env gene alleles compared. The variable regions range in homology from 42% (A compared to B) to 57% (C compared to E) in pairwise comparisons; the flanking conserved domains are on average 95% homologous. The sequences of three different subgroup B virus isolates are highly homologous in both the conserved and variable regions. Secondary structure predictions suggest that gp85 is composed mostly of beta sheet topology. Hydrophilic loops within the variable regions may define sites of receptor interaction and binding sites for subgroup specific neutralizing antibodies.

Alleles↗

PubMedDate not supplied

Construction of a broad host range shuttle vector for gene cloning and expression in Actinobacillus pleuropneumoniae and other Pasteurellaceae.

We have constructed a pair of broad host range expression vectors, pJFF224-NX and pJFF224-XN, based on plasmid RSF1010, which enable cloning and efficient expression of genes in Actinobacillus pleuropneumoniae and Pasteurella haemolytica and in Escherichia coli. The vectors consist of the minimal autonomous replicon of the broad host range plasmid RSF1010 and a type II chloramphenicol acetyl transferase gene for chloramphenicol resistance selection. In addition, they contain a gene expression cassette based on the E. coli bacteriophage T4 gene 32 promoter region and a transcription stop signal, which are separated by a segment of multiple cloning sites in both orientations. Electroporation and subsequent selection for chloramphenicol resistance was used for the introduction of the vectors in A. pleuropneumoniae and P. haemolytica. A promoterless xy/E gene from the Pseudomonas putida TOL plasmid was cloned onto pJFF224-NX. This plasmid enabled efficient expression of active catechol2,3oxygenase in A. pleuropneumoniae and P. haemolytica. It was stably maintained in A. pleuropneumoniae without antibiotic selection, showing less than 0.1% loss after 100 generations, while native RSF1010 and other RSF1010-based vectors were unstable in this host.

Actinobacillus pleuropneumoniae↗

PubMed1990

[Localization in Escherichia coli of transcribed regions of the broad host range plasmid pBS222].

The set of insertions of the CmR-gene region devoid of the promoter into the broad host-range plasmid pBS222 regions transcribed in Escherichia coli cells has been obtained and characterized. Three transcribed regions of the plasmid that are dispensable for life functions of the plasmid have been identified by the insertions technique. The deleted plasmid derivatives have been isolated suitable for using as the broad host-range vectors.

Chloramphenicol Resistance↗

PubMed2006

Cultivation-independent examination of horizontal transfer and host range of an IncP-1 plasmid among gram-positive and gram-negative bacteria indigenous to the barley rhizosphere.

The host range and transfer frequency of an IncP-1 plasmid (pKJK10) among indigenous bacteria in the barley rhizosphere was investigated. A new flow cytometry-based cultivation-independent method for enumeration and sorting of transconjugants for subsequent 16S rRNA gene classification was used. Indigenous transconjugant rhizosphere bacteria were collected by fluorescence-activated cell sorting and identified by cloning and sequencing of 16S rRNA genes from the sorted cells. The host range of the pKJK10 plasmid was exceptionally broad, as it included not only bacteria belonging to the alpha, beta, and gamma subclasses of the Proteobacteria, but also Arthrobacter sp., a gram-positive member of the Actinobacteria. The transfer frequency (transconjugants per donor) from the Pseudomonas putida donor to the indigenous bacteria was 7.03 x 10(-2) +/- 3.84 x 10(-2). This is the first direct documentation of conjugal transfer between gram-negative donor and gram-positive recipient bacteria in situ.

Conjugation, Genetic↗

PubMed2004

VEX-capture: a new technique that allows in vivo excision, cloning, and broad-host-range transfer of large bacterial genomic DNA segments.

We have developed a novel and easily performed procedure for the targeted excision, cloning, and broad-host-range transfer of large bacterial genomic DNA segments. This procedure, called Vector-mediated excision and Capture (VEX-Capture), represents a new molecular tool for the convenient manipulation and exchange of large (20-40+ kb) bacterial genomic fragments. VEX-Capture utilizes lox/Cre-mediated site-specific recombination for excision of the targeted genomic segment and homologous recombination for cloning of the excised DNA section onto a self-transmissible, broad-host-range IncP plasmid. The "captured" genomic DNA segment can then be transferred to a wide variety of Gram-negative hosts for basic research and bioengineering purposes. To demonstrate the utility and function of VEX-Capture, we have excised and cloned three separate genomic islands from the Salmonella typhimurium chromosome ranging in size from 26.7 to 40.0 kb. To test the ability of these islands to be established in different bacterial hosts, we transferred them to six other Gram-negative species and monitored their establishment via phenotypic and molecular analysis. RT-PCR was used to assay the expression of selected S. typhimurium island genes in the different species. This analysis led to the discovery that an island-encoded master regulator of S. typhimurium virulence functions is expressed in a species-specific manner. Our results demonstrate the potential for VEX-Capture to be used as a convenient genetic technique for fundamental biological applications in a wide variety of bacterial species.

Chromosomes, Bacterial↗

PubMed1989

Evidence for the role of the P2 protein of human rhinovirus in its host range change.

Human rhinovirus 39 (HRV39) is blocked in nonpermissive L cells at both adsorption and intracellular replication steps. We have selected a host range variant of HRV39 capable of bypassing the intracellular replication block and found it to have altered nonstructural P2 proteins. These alterations are similar to those reported earlier for host range variants of HRV2 (F. H. Yin and N. B. Lomax, J. Virol. 48:410-418, 1983). This observation suggests that the intracellular replication block for both HRV2 and HRV39 in mouse L cells is at the same step. We propose that the P2 protein is an essential viral component that cannot function in mouse L cells unless altered. This alteration occurs spontaneously in stocks of HRV39 during growth in permissive HeLa cells.

Capsid↗

PubMed2003

Parvovirus host range, cell tropism and evolution.

The past few years have seen major advances in our understanding of the controls of evolution, host range and cell tropism of parvoviruses. Notable findings have included the identification of the transferrin receptor TfR as the cell surface receptor for canine parvovirus and feline panleukopenia virus, and also the finding that specific binding to the canine TfR led to the emergence of canine parvovirus as a new pathogen in dogs. The structures of the adeno-associated virus-2 and porcine parvovirus capsids, along with those of the minute virus of mice, have also advanced our understanding of parvovirus biology. Structure-function studies have shown that in several different parvoviruses the threefold spikes or peaks of the capsid control several aspects of cell tropism and host range, and that those are subject to selective pressures leading to viral evolution. The cell and tissue tropisms of different adeno-associated virus serotypes were demonstrated to be due, in part, to specific receptor binding.

Animals↗

PubMed2005

Isolation of lactococcal prolate phage-phage recombinants by an enrichment strategy reveals two novel host range determinants.

Virulent lactococcal prolate (or c2-like) phages are the second most common phage group that causes fermentation failure in the dairy industry. We have mapped two host range determinants in two lactococcal prolate phages, c2 and 923, for the host strains MG1363 and 112. Each phage replicates on only one of the two host strains: c2 on MG1363 and 923 on 112. Phage-phage recombinants that replicated on both strains were isolated by a new method that does not require direct selection but rather employs an enrichment protocol. After initial mixed infection of strain 112, two rotations, the first of which was carried out on strain MG1363 and the second on 112, permitted continuous amplification of double-plating recombinants while rendering one of the parent phages unamplified in each of the two rotations. Mapping of the recombination endpoints showed that the presence of the N-terminal two-thirds of the tail protein L10 of phage c2 and a 1,562-bp cosR-terminal fragment of phage 923 genome overcame blocks of infection in strains MG1363 and 112, respectively. Both infection inhibition mechanisms act at the stage of DNA entry; in strain MG1363, the infection block acts early, before phage DNA enters the cytoplasm, and in strain 112, it acts late, after most of the DNA has entered the cell but before it undergoes cos-end ligation. These are the first reported host range determinants in bacteriophage of lactic acid bacteria required for overcoming inhibition of infection at the stage of DNA entry and cos-end ligation.

Bacteriophages↗