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Virology Journal Feb 2016The genus Tobamovirus (Virgaviridae) comprises 33 accepted species with the recent addition of eight new viruses and is divided in to three subgroups based on the origin...
BACKGROUND
The genus Tobamovirus (Virgaviridae) comprises 33 accepted species with the recent addition of eight new viruses and is divided in to three subgroups based on the origin of assembly of the virion and host range. Within the subgroup 1 tobamoviruses the orchid-associated tobamovirus was hypothesized to be a chimeric derivative of recombinations between genome fragments from subgroup 3 and 1. Recombination events involving RdRp, movement and coat protein genes are recorded within subgroup 1 and 2. However natural recombinations have not previously been reported between subgroup 3 tobamoviruses.
FINDINGS
The organization and phylogenetic analyses of the complete genome and the different ORFs placed the new isolate within the Ribgrass mosaic virus clade of subgroup 3 tobamoviruses. Recombination detection analyses indicated that the isolate was a chimeric genome with fragments of high similarity to Ribgrass mosaic virus (RMV) strains NZ-439 (HQ667978) and Actinidia-AC (GQ401365.1) infecting herbaceous Plantago sp. and woody Actinidia spp., respectively. The recombinant differed across the whole genome by 3-8 % from other published RMV genomes.
CONCLUSION
In this investigation we report an intra-specific recombination between RMV strains NZ-439 (HQ667978) and Actinidia-AC (GQ401365.1), in the replicase component between viral-methyltransferase and viral-helicase regions, resulting in a novel RMV strain FSHS (JQ319720.1) that represents the first described natural recombinant within the RMV cluster of subgroup 3 tobamoviruses.
Topics: Genome, Viral; Open Reading Frames; Phylogeny; Recombination, Genetic; Tobamovirus
PubMed: 26891841
DOI: 10.1186/s12985-016-0487-5 -
Journal of Virology May 2014Recombination plays a critical role in virus evolution. It helps avoid genetic decline and creates novel phenotypes. This promotes survival, and genome sequencing...
UNLABELLED
Recombination plays a critical role in virus evolution. It helps avoid genetic decline and creates novel phenotypes. This promotes survival, and genome sequencing suggests that recombination has facilitated the evolution of human pathogens, including orthopoxviruses such as variola virus. Recombination can also be used to map genes, but although recombinant poxviruses are easily produced in culture, classical attempts to map the vaccinia virus (VACV) genome this way met with little success. We have sequenced recombinants formed when VACV strains TianTan and Dryvax are crossed under different conditions. These were a single round of growth in coinfected cells, five rounds of sequential passage, or recombinants obtained using leporipoxvirus-mediated DNA reactivation. Our studies showed that recombinants contain a patchwork of DNA, with the number of exchanges increasing with passage. Further passage also selected for TianTan DNA and correlated with increased plaque size. The recombinants produced through a single round of coinfection contain a disproportionate number of short conversion tracks (<1 kbp) and exhibited 1 exchange per 12 kbp, close to the ∼1 per 8 kbp in the literature. One by-product of this study was that rare mutations were also detected; VACV replication produces ∼1×10(-8) mutation per nucleotide copied per cycle of replication and ∼1 large (21 kbp) deletion per 70 rounds of passage. Viruses produced using DNA reactivation appeared no different from recombinants produced using ordinary methods. An attractive feature of this approach is that when it is combined with selection for a particular phenotype, it provides a way of mapping and dissecting more complex virus traits.
IMPORTANCE
When two closely related viruses coinfect the same cell, they can swap genetic information through a process called recombination. Recombination produces new viruses bearing different combinations of genes, and it plays an important role in virus evolution. Poxviruses are a family of viruses that includes variola (or smallpox) virus, and although poxviruses are known to recombine, no one has previously mapped the patterns of DNAs exchanged between viruses. We coinfected cells with two different vaccinia poxviruses, isolated the progeny, and sequenced them. We show that poxvirus recombination is a very accurate process that assembles viruses containing DNA copied from both parents. In a single round of infection, DNA is swapped back and forth ∼18 times per genome to make recombinant viruses that are a mosaic of the two parental DNAs. This mixes many different genes in complex combinations and illustrates how recombination can produce viruses with greatly altered disease potential.
Topics: Animals; Cell Line; Crosses, Genetic; DNA, Viral; Genome, Viral; Mutation Rate; Recombination, Genetic; Sequence Analysis, DNA; Serial Passage; Vaccinia virus
PubMed: 24574414
DOI: 10.1128/JVI.00022-14 -
Molecular Biology and Evolution Jan 2018Identifying recombinant sequences in an era of large genomic databases is challenging as it requires an efficient algorithm to identify candidate recombinants and...
Identifying recombinant sequences in an era of large genomic databases is challenging as it requires an efficient algorithm to identify candidate recombinants and parents, as well as appropriate statistical methods to correct for the large number of comparisons performed. In 2007, a computation was introduced for an exact nonparametric mosaicism statistic that gave high-precision P values for putative recombinants. This exact computation meant that multiple-comparisons corrected P values also had high precision, which is crucial when performing millions or billions of tests in large databases. Here, we introduce an improvement to the algorithmic complexity of this computation from O(mn3) to O(mn2), where m and n are the numbers of recombination-informative sites in the candidate recombinant. This new computation allows for recombination analysis to be performed in alignments with thousands of polymorphic sites. Benchmark runs are presented on viral genome sequence alignments, new features are introduced, and applications outside recombination analysis are discussed.
Topics: Algorithms; Gene Rearrangement; Phylogeny; Recombination, Genetic; Sequence Alignment; Sequence Analysis, DNA; Software
PubMed: 29029186
DOI: 10.1093/molbev/msx263 -
Scientific Reports Mar 2019Human adenovirus (HAdV) group C are the common etiologic in infants with severe acute respiratory infections (SARI). In the study, we report that a novel recombinant...
Human adenovirus (HAdV) group C are the common etiologic in infants with severe acute respiratory infections (SARI). In the study, we report that a novel recombinant HAdV-C group strain (SH2016) was isolated from an infant with SARI in Shanghai in Feb. 4, 2016. The whole-genome sequence of SH2016 strain was generated and compared to other HAdV genomes publicly available. The strain SH2016 genome contains 35,946 nucleotides and coded 40 putative proteins, which was divided into 11 regions. RDP and phylogenetic analyses of the complete genome showed that the SH2016 strain was arranged into a novel subtype and might be recombined with HAdV-1 and HAdV-2. Our finding indicated that the frequent recombination among the HAdV-C group played an important role in driving force for polymorphism of human HAdV-C group prevalent in Shanghai, China. Further epidemiological surveillance of HAdV-C group is necessary to explore whether the novel HAdV-C group will maintain long-term stability. And the pathogenicity and clinical characteristics of the novel HAdV-C group member should be done more.
Topics: Adenoviridae Infections; Adenoviruses, Human; Algorithms; China; DNA, Viral; Genome, Viral; Humans; Phylogeny; Recombination, Genetic; Respiratory Tract Infections; Whole Genome Sequencing
PubMed: 30862832
DOI: 10.1038/s41598-018-37756-4 -
Scientific Reports Jan 2024Genetic recombination is one of the major evolution processes of HIV-1. Despite their great genetic divergence, HIV-1 groups M and O can generate HIV-1/MO intergroup...
Genetic recombination is one of the major evolution processes of HIV-1. Despite their great genetic divergence, HIV-1 groups M and O can generate HIV-1/MO intergroup recombinants. The current description of 20 HIV-1/MO unique recombinant forms suggests a possible benefit of the recombination. The aim of this work was to study in vitro the replicative potential of HIV-1/MO recombinant forms. This analysis was based on a simple recombination pattern, [O-M], harboring a breakpoint in Vpr. A chimeric infectious molecular clone, pOM-TB-2016 was synthesized from HIV-1/M subtype B and HIV-1/O subgroup T and recombinant viruses were obtained by transfection/co-culture. To compare the replicative potential of these viruses, two markers were monitored in culture supernatants: Reverse Transcriptase (RT) activity and P24 antigen concentration. The results showed a superiority of the group M parental virus compared to group O for both markers. In contrast, for the recombinant virus, RT activity data did not overlap with the concentration of P24 antigen, suggesting a hybrid behavior of the recombinant, in terms of enzyme activity and P24 production. These results highlighted many hypotheses about the impact of recombination on replicative potential and demonstrated again the significant plasticity of HIV genomes and their infinite possibility of evolution.
Topics: Humans; HIV-1; HIV Infections; Recombination, Genetic; HIV Seropositivity; Orthopoxvirus; Parents
PubMed: 38242913
DOI: 10.1038/s41598-024-51873-3 -
Nucleic Acids Research Apr 2015Recombinant adenoviruses containing a double-stranded DNA genome of 26-45 kb were broadly explored in basic virology, for vaccination purposes, for treatment of tumors...
Recombinant adenoviruses containing a double-stranded DNA genome of 26-45 kb were broadly explored in basic virology, for vaccination purposes, for treatment of tumors based on oncolytic virotherapy, or simply as a tool for efficient gene transfer. However, the majority of recombinant adenoviral vectors (AdVs) is based on a small fraction of adenovirus types and their genetic modification. Recombineering techniques provide powerful tools for arbitrary engineering of recombinant DNA. Here, we adopted a seamless recombineering technology for high-throughput and arbitrary genetic engineering of recombinant adenoviral DNA molecules. Our cloning platform which also includes a novel recombination pipeline is based on bacterial artificial chromosomes (BACs). It enables generation of novel recombinant adenoviruses from different sources and switching between commonly used early generation AdVs and the last generation high-capacity AdVs lacking all viral coding sequences making them attractive candidates for clinical use. In combination with a novel recombination pipeline allowing cloning of AdVs containing large and complex transgenes and the possibility to generate arbitrary chimeric capsid-modified adenoviruses, these techniques allow generation of tailored AdVs with distinct features. Our technologies will pave the way toward broader applications of AdVs in molecular medicine including gene therapy and vaccination studies.
Topics: Adenoviridae; Chromosomes, Artificial, Bacterial; Cloning, Molecular; DNA, Viral; Genetic Engineering; Genetic Vectors; HEK293 Cells; Humans; Recombination, Genetic
PubMed: 25609697
DOI: 10.1093/nar/gkv031 -
Scientific Reports Jan 2019Shewanella oneidensis MR-1 is an invaluable host for the discovery and engineering of pathways important for bioremediation of toxic and radioactive metals and...
Shewanella oneidensis MR-1 is an invaluable host for the discovery and engineering of pathways important for bioremediation of toxic and radioactive metals and understanding extracellular electron transfer. However, genetic manipulation is challenging due to the lack of genetic tools. Previously, the only reliable method used for introducing DNA into Shewanella spp. at high efficiency was bacterial conjugation, enabling transposon mutagenesis and targeted knockouts using suicide vectors for gene disruptions. Here, we describe development of a robust and simple electroporation method in S. oneidensis that allows an efficiency of ~4.0 x 10 transformants/µg DNA. High transformation efficiency is maintained when cells are frozen for long term storage. In addition, we report a new prophage-mediated genome engineering (recombineering) system using a λ Red Beta homolog from Shewanella sp. W3-18-1. By targeting two different chromosomal alleles, we demonstrate its application for precise genome editing using single strand DNA oligonucleotides and show that an efficiency of ~5% recombinants among total cells can be obtained. This is the first effective and simple strategy for recombination with markerless mutations in S. oneidensis. Continued development of this recombinant technology will advance high-throughput and genome modification efforts to engineer and investigate S. oneidensis and other environmental bacteria.
Topics: Electroporation; Gene Editing; Genetics, Microbial; Oligonucleotides; Recombination, Genetic; Shewanella
PubMed: 30631105
DOI: 10.1038/s41598-018-37025-4 -
PLoS Genetics Jun 2018Homologous recombination in the genetic transformation model organism Streptococcus pneumoniae is thought to be important in the adaptation and evolution of this...
Homologous recombination in the genetic transformation model organism Streptococcus pneumoniae is thought to be important in the adaptation and evolution of this pathogen. While competent pneumococci are able to scavenge DNA added to laboratory cultures, large-scale transfers of multiple kb are rare under these conditions. We used whole genome sequencing (WGS) to map transfers in recombinants arising from contact of competent cells with non-competent 'target' cells, using strains with known genomes, distinguished by a total of ~16,000 SNPs. Experiments designed to explore the effect of environment on large scale recombination events used saturating purified donor DNA, short-term cell assemblages on Millipore filters, and mature biofilm mixed cultures. WGS of 22 recombinants for each environment mapped all SNPs that were identical between the recombinant and the donor but not the recipient. The mean recombination event size was found to be significantly larger in cell-to-cell contact cultures (4051 bp in filter assemblage and 3938 bp in biofilm co-culture versus 1815 bp with saturating DNA). Up to 5.8% of the genome was transferred, through 20 recombination events, to a single recipient, with the largest single event incorporating 29,971 bp. We also found that some recombination events are clustered, that these clusters are more likely to occur in cell-to-cell contact environments, and that they cause significantly increased linkage of genes as far apart as 60,000 bp. We conclude that pneumococcal evolution through homologous recombination is more likely to occur on a larger scale in environments that permit cell-to-cell contact.
Topics: Cell Communication; DNA; Evolution, Molecular; Gene Rearrangement; Genome, Bacterial; Homologous Recombination; Polymorphism, Single Nucleotide; Recombination, Genetic; Streptococcus pneumoniae; Whole Genome Sequencing
PubMed: 29897968
DOI: 10.1371/journal.pgen.1007410 -
Cell Nov 1986We have investigated RNA recombination among poliovirus genomes by analyzing both intratypic and intertypic recombinant crosses involving the same defined genetic...
We have investigated RNA recombination among poliovirus genomes by analyzing both intratypic and intertypic recombinant crosses involving the same defined genetic markers. Sequence analysis of the recombinant junctions of 13 nonsibling intertypic recombinants showed that intertypic RNA recombination is not site-specific, nor does it require extensive homology between the recombining parents at the crossover site. To discriminate between breaking-rejoining and copy choice mechanisms of RNA recombination, we have inhibited the replication of the recombining parents independently and found opposite effects on the frequency of genetic recombination in intratypic crosses. The results strongly support a copy choice mechanism for RNA recombination, in which the viral RNA polymerase switches templates during negative strand synthesis.
Topics: Base Sequence; Chromosome Mapping; Crosses, Genetic; Cytopathogenic Effect, Viral; DNA-Directed RNA Polymerases; Genetic Markers; Mutation; Poliovirus; RNA, Viral; Recombination, Genetic; Structure-Activity Relationship
PubMed: 3021340
DOI: 10.1016/0092-8674(86)90600-8 -
Scientific Reports Sep 2015The T-DNA region of pMF1 vector of marker-free system developed by Wageningen UR, has Recombinase R-LBD gene fusion and nptII and codA gene fusion between two...
The T-DNA region of pMF1 vector of marker-free system developed by Wageningen UR, has Recombinase R-LBD gene fusion and nptII and codA gene fusion between two recombination sites. After transformation applying dexamethasone (DEX) can activate the recombinase to remove the T-DNA fragment between recombination sites. The recombinant ought to be selected on 5-fluorocytocine (5-FC) because of codA converting 5-FC into 5-fluorouracil the toxic. A PMF1 vector was transformed into hexaploid species Crambe abyssinica. Two independent transformants were chosen for DEX-induced recombination and later 5-FC selection. In contrast to earlier pMF1 experiments, the strategy of stepwise selection based on meristematic regeneration was engaged. After a long period of 5-FC selection, recombinants were obtained successfully, but most of the survivors were wildtype and non-recombinant. The results revealed when applying the PMF1 marker-free system on C. abyssinica, 1) Increasing in the DEX concentration did not correspondingly enhance the success of recombination; 2) both of the DEX-induced recombination and 5-FC negative selection were apparently insufficient which was leading to the extremely high frequency in chimerism occurring for recombinant and non-recombinant cells in tissues; 3) the strategy of stepwise selection based on meristem tissue regeneration was crucial for successfully isolating the recombinant germplasm from the chimera.
Topics: DNA, Bacterial; Dexamethasone; Fluorouracil; Genetic Vectors; Meristem; Phenotype; Plants, Genetically Modified; Recombination, Genetic; Regeneration; Tracheophyta; Transformation, Genetic
PubMed: 26358007
DOI: 10.1038/srep14033