Identification of a novel single-stranded circular DNA virus in pig feces.
ABSTRACT: Porcine stool-associated circular virus 5 (PoSCV5) was detected in the feces of a pig with diarrhea. The complete 3,062-nucleotide genome contains two bidirectionally transcribed open reading frames (ORFs). Phylogenetic analysis of the deduced replication initiator protein (Rep) places PoSCV5 alone on a deep branch among the small circular Rep-encoding single-stranded DNA viruses.
Project description:Using metagenomics and molecular cloning methods, we characterized five novel small, circular viral genomes from pig feces that are distantly related to chimpanzee and porcine stool-associated circular viruses, (ChiSCV and PoSCV1). Phylogenetic analysis placed these viruses into a highly divergent clade of this rapidly growing new viral family. This new clade of viruses, provisionally named porcine stool-associated circular virus 2 and 3 (PoSCV2 and PoSCV3), encodes a stem-loop structure (presumably the origin of DNA replication) in the small intergenic region and a replication initiator protein commonly found in other biological systems that replicate their genomes via the rolling-circle mechanism. Furthermore, these viruses also exhibit three additional overlapping open reading frames in the large intergenic region between the capsid and replication initiator protein genes.
Project description:Using a metagenomic approach and molecular cloning methods, we identified, cloned, and sequenced the complete genome of a novel circular DNA virus, porcine stool-associated virus (PoSCV4), from pig feces. Phylogenetic analysis of the deduced replication initiator protein showed that PoSCV4 is most related to a fur seal feces-associated circular DNA virus.
Project description:The genomes of numerous circoviruses and distantly related circular ssDNA viruses encoding a rolling circle replication initiator protein (Rep) have been characterized from the tissues of mammals, fish, insects, plants (geminivirus and nanovirus), in human and animal feces, in an algae cell, and in diverse environmental samples. We review the genome organization, phylogenetic relationships and initial prevalence studies of cycloviruses, a proposed new genus in the Circoviridae family. Viral fossil rep sequences were also recently identified integrated on the chromosomes of mammals, frogs, lancelets, crustaceans, mites, gastropods, roundworms, placozoans, hydrozoans, protozoans, land plants, fungi, algae, and phytoplasma bacterias and their plasmids, reflecting the very wide past host range of rep bearing viruses. An ancient origin for viruses with Rep-encoding small circular ssDNA genomes, predating the diversification of eukaryotes, is discussed. The cellular hosts and pathogenicity of many recently described rep-containing circular ssDNA genomes remain to be determined. Future studies of the virome of single cell and multi-cellular eukaryotes are likely to further extend the known diversity and host-range of small rep-containing circular ssDNA viral genomes.
Project description:Viral metagenomics has recently revealed the ubiquitous and diverse nature of single-stranded DNA (ssDNA) viruses that encode a conserved replication initiator protein (Rep) in the marine environment. Although eukaryotic circular Rep-encoding ssDNA (CRESS-DNA) viruses were originally thought to only infect plants and vertebrates, recent studies have identified these viruses in a number of invertebrates. To further explore CRESS-DNA viruses in the marine environment, this study surveyed CRESS-DNA viruses in various marine invertebrate species. A total of 27 novel CRESS-DNA genomes, with Reps that share less than 60.1% identity with previously reported viruses, were recovered from 21 invertebrate species, mainly crustaceans. Phylogenetic analysis based on the Rep revealed a novel clade of CRESS-DNA viruses that included approximately one third of the marine invertebrate associated viruses identified here and whose members may represent a novel family. Investigation of putative capsid proteins (Cap) encoded within the eukaryotic CRESS-DNA viral genomes from this study and those in GenBank demonstrated conserved patterns of predicted intrinsically disordered regions (IDRs), which can be used to complement similarity-based searches to identify divergent structural proteins within novel genomes. Overall, this study expands our knowledge of CRESS-DNA viruses associated with invertebrates and explores a new tool to evaluate divergent structural proteins encoded by these viruses.
Project description:The Smacoviridae has recently been classified as a family of small circular single-stranded DNA viruses. An increasing number of smacovirus genomes have been identified exclusively in faecal matter of various vertebrate species and from insect body parts. However, the genetic diversity and host range of smacoviruses remains to be fully elucidated. Herein, we report the genetic characterization of eleven circular replication-associated protein (Rep) encoding single-stranded (CRESS) DNA viruses detected in the faeces of Zambian non-human primates. Based on pairwise genome-wide and amino acid identities with reference smacovirus species, ten of the identified CRESS DNA viruses are assigned to the genera Porprismacovirus and Huchismacovirus of the family Smacoviridae, which bidirectionally encode two major open reading frames (ORFs): Rep and capsid protein (CP) characteristic of a type IV genome organization. The remaining unclassified CRESS DNA virus was related to smacoviruses but possessed a genome harbouring a unidirectionally oriented CP and Rep, assigned as a type V genome organization. Moreover, phylogenetic and recombination analyses provided evidence for recombination events encompassing the 3'-end of the Rep ORF in the unclassified CRESS DNA virus. Our findings increase the knowledge of the known genetic diversity of smacoviruses and highlight African non-human primates as carrier animals.
Project description:Replication initiation of nanoviruses, plant viruses with a multipartite circular single-stranded DNA genome, is triggered by the master Rep (M-Rep) protein. To enable the study of interactions between M-Rep and viral or host factors involved in replication, we designed oligohistidine-tagged variants of the nanovirus Faba bean necrotic yellows virus (FBNYV) M-Rep protein that allow affinity purification of enzymatically active M-Rep from plant tissue. The tagged M-Rep protein was able to initiate replication of its cognate and other FBNYV DNAs in Nicotiana benthamiana leaf disks and plants. The replicon encoding the tagged M-Rep protein multiplied and moved systemically in FBNYV-infected Vicia faba plants and was transmitted by the aphid vector of the virus. Using the tagged M-Rep protein, we demonstrated the in planta interaction between wild-type M-Rep and its tagged counterpart. Such a tagged and fully functional replication initiator protein will have bearings on the isolation of protein complexes from plants.
Project description:Gelatinous zooplankton, such as ctenophores and jellyfish, are important components of marine and brackish ecosystems and play critical roles in aquatic biogeochemistry. As voracious predators of plankton, ctenophores have key positions in aquatic food webs and are often successful invaders when introduced to new areas. Gelatinous zooplankton have strong impacts on ecosystem services, particularly in coastal environments. However, little is known about the factors responsible for regulating population dynamics of gelatinous organisms, including biological interactions that may contribute to bloom demise. Ctenophores are known to contain specific bacterial communities and a variety of invertebrate parasites and symbionts; however, no previous studies have examined the presence of viruses in these organisms. Building upon recent studies demonstrating a diversity of single-stranded DNA viruses that encode a replication initiator protein (Rep) in aquatic invertebrates, this study explored the presence of circular, Rep-encoding single-stranded DNA (CRESS-DNA) viruses in the ctenophores Mnemiopsis leidyi and Beroe ovata collected from the Skidaway River Estuary and Savannah River in Georgia, USA. Using rolling circle amplification followed by restriction enzyme digestion, this study provides the first evidence of viruses in ctenophores. Investigation of four CRESS-DNA viruses over an 8-month period using PCR demonstrated temporal trends in viral prevalence and indicated that some of the viruses may persist in ctenophore populations throughout the year. Although future work needs to examine the ecological roles of these ctenophore-associated viruses, this study indicates that viral infection may play a role in population dynamics of gelatinous zooplankton.
Project description:Here, we present the complete genome sequences of three circular replication-associated protein (Rep)-encoding single-stranded DNA (CRESS DNA) viruses detected in secondary treated and disinfected wastewater effluent. The discovered viruses, named wastewater CRESS DNA virus (WCDV)-1 to -3, represent novel viral species that seem to persist in wastewater effluent.
Project description:Metagenomic analysis of diarrhea samples revealed the presence of numerous human enteric viruses and small circular Rep-encoding single-stranded DNA (CRESS-DNA) genomes. One such genome was related to smacoviruses, while eight others were related to genomes reported in the feces of different mammals. The tropism of these CRESS-DNA viruses remains unknown.
Project description:Circoviruses are highly prevalent porcine and avian pathogens. In recent years, novel circular ssDNA genomes have recently been detected in a variety of fecal and environmental samples using deep sequencing approaches. In this study the identification of genomes of novel circoviruses and cycloviruses in feces of insectivorous bats is reported. Pan-reactive primers were used targeting the conserved rep region of circoviruses and cycloviruses to screen DNA bat fecal samples. Using this approach, partial rep sequences were detected which formed five phylogenetic groups distributed among the Circovirus and the recently proposed Cyclovirus genera of the Circoviridae. Further analysis using inverse PCR and Sanger sequencing led to the characterization of four new putative members of the family Circoviridae with genome size ranging from 1,608 to 1,790 nt, two inversely arranged ORFs, and canonical nonamer sequences atop a stem loop.