The Genome Segments of Bluetongue Virus Differ in Copy Number in a Host-Specific Manner

ABSTRACT Genome segmentation is mainly thought to facilitate reassortment. Here, we show that segmentation can also allow differences in segment abundance in populations of bluetongue virus (BTV). BTV has a genome consisting in 10 segments, and its cycle primarily involves periodic alternation between ruminants and Culicoides biting midges. We have developed a reverse transcription-quantitative PCR (RT-qPCR) approach to quantify each segment in wild BTV populations sampled in both ruminants and midges during an epizootic. Segment frequencies deviated from equimolarity in all hosts. Interestingly, segment frequencies were reproducible and distinct between ruminants and biting midges. Beyond a putative regulatory role in virus expression, this phenomenon could lead to different evolution rates between segments. IMPORTANCE The variation in viral gene frequencies remains a largely unexplored aspect of within-host genetics. This phenomenon is often considered to be specific to multipartite viruses. Multipartite viruses have segmented genomes, but in contrast to segmented viruses, their segments are each encapsidated alone in a virion. A main hypothesis explaining the evolution of multipartism is that, compared to segmented viruses, it facilitates the regulation of segment abundancy, and the genes the segments carry, within a host. These differences in gene frequencies could allow for expression regulation. Here, we show that wild populations of a segmented virus, bluetongue virus (BTV), also present unequal segment frequencies. BTV cycles between ruminants and Culicoides biting midges. As expected from a role in expression regulation, segment frequencies tended to show specific values that differed between ruminants and midges. Our results expand previous knowledge on gene frequency variation and call for studies on its role and conservation beyond multipartite viruses.

Download Full-text

Development of Multiwalled Carbon Nanotube-Based Immunobiosensor for the Detection of Bluetongue Virus

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.19000 ◽

2021 ◽

Vol 21 (6) ◽

pp. 3513-3523

Author(s):

Madhu Sudan Guray ◽

Prasad Minakshi ◽

Basanti Brar ◽

Ruma Rani ◽

Upendra P. Lambe

Keyword(s):

Carbon Nanotube ◽

Bluetongue Virus ◽

Diagnostic Methods ◽

Multiwalled Carbon Nanotube ◽

Virus Propagation ◽

Multiwalled Carbon ◽

Biting Midges ◽

Animal Products ◽

Self Assembled Layer ◽

The Cost

Bluetongue (BT) disease is a noncontagious disease of domestic and wild ruminants (mainly sheep, cattle, deer) caused by the bluetongue virus (BTV) which is an orbivirus of the Reoviridae family and transmitted by vector Culicoides biting midges. It is a reportable disease of considerable socioeconomic concern and of major importance for the international trade of animals and animal products. Conventional diagnostic methods, such as virus propagation and isolation, immunoassays and also various molecular methods have been developed for the detection of the BTV. Here, we present a novel, rapid and pen-side test for the detection of BTV using multiwalled carbon nanotube (MWCNTs) based immunosensor. Though it is not reported yet. The MWCNTs were prepared, characterized and functionalized with carboxyl group. Viral antibodies were conjugated successfully with functionalized MWCNTs and coated on screen printed carbon electrode (SPCE). These SPCE were evaluated by using electrochemical sensor with an antigen specific to BTV antibodies, resulted in the self-assembled layer of antigen–antibody on the surface of SPCE. The approach described in the present study is a prototype for the development of simple and economic diagnostic tool which will provide the routine screening of BT disease at the door of farmers, thereby increasing the income of farmers by decreasing the cost of diagnosis.

Download Full-text

Measurement of the Infection and Dissemination of Bluetongue Virus in Culicoides Biting Midges Using a Semi-Quantitative RT-PCR Assay and Isolation of Infectious Virus

PLoS ONE ◽

10.1371/journal.pone.0070800 ◽

2013 ◽

Vol 8 (8) ◽

pp. e70800 ◽

Cited By ~ 35

Author(s):

Eva Veronesi ◽

Frank Antony ◽

Simon Gubbins ◽

Nick Golding ◽

Alison Blackwell ◽

...

Keyword(s):

Bluetongue Virus ◽

Infectious Virus ◽

Rt Pcr ◽

Pcr Assay ◽

Biting Midges ◽

Culicoides Biting Midges

Download Full-text

Seasonal dynamics of biting midges (Diptera: Ceratopogonidae: Culicoides), the potential vectors of bluetongue virus, in Sweden

Veterinary Parasitology ◽

10.1016/j.vetpar.2011.08.009 ◽

2012 ◽

Vol 184 (1) ◽

pp. 59-67 ◽

Cited By ~ 43

Author(s):

M. Ander ◽

R. Meiswinkel ◽

J. Chirico

Keyword(s):

Seasonal Dynamics ◽

Bluetongue Virus ◽

Biting Midges

Download Full-text

High frequency variation in mammary tumor virus expression in cell culture

Cell ◽

10.1016/0092-8674(76)90189-6 ◽

1976 ◽

Vol 8 (1) ◽

pp. 87-93 ◽

Cited By ~ 13

Author(s):

Wade P. Parks ◽

Elizabeth S. Hubbell ◽

Robert J. Goldberg ◽

Frank J. O'Neill ◽

Edward M. Scolnick

Keyword(s):

Cell Culture ◽

Mammary Tumor ◽

High Frequency ◽

Frequency Variation ◽

Mammary Tumor Virus ◽

Tumor Virus ◽

Virus Expression

Download Full-text

The evolution of bluetongue virus: genetic and phenotypic diversity of field strains

Polish Journal of Veterinary Sciences ◽

10.2478/pjvs-2013-0086 ◽

2013 ◽

Vol 16 (3) ◽

pp. 611-616 ◽

Cited By ~ 2

Author(s):

W. Niedbalski

Keyword(s):

Genetic Drift ◽

Bluetongue Virus ◽

Phenotypic Diversity ◽

Intragenic Recombination ◽

Insect Vector ◽

Phenotypic Properties ◽

A Genome ◽

Different Strains ◽

The Individual ◽

Genetic Shift

AbstractBluetongue virus (BTV), the aetiological agent of bluetongue (BT), is a small (about 70 nm in diameter) icosahedral virus with a genome composed of ten linear segments of double-stranded RNA (dsRNA), which is packaged within an icosahedral nucleocapsid composed of seven structural proteins. The BTV genome evolves rapidly via genetic drift, reassortment of genome segments (genetic shift) and intragenic recombination. This evolution, and random fixation of quasispecies variants during transmission of BTV between susceptible animals and vectors appear to be the main mechanism leading to the observed genetic diversity amongst BTV field strains. The individual BTV gene segments evolve independently of one another by genetic drift in a host-specific fashion, generating quasispecies populations in both ruminant and insect hosts. Reassortment of BTV genes is responsible for genetic shift among strains of BTV, and has been demonstrated after infection of either the ruminant host or insect vector with different strains or serotypes of BTV. Intragenetic recombination, whereby mosaic genes are generated from the “splicing” together of homologous genes from different ancestral viral strains, has been demonstrated for BTV. The genetic variation of BTV is likely responsible for differences in the virulence and other phenotypic properties of individual field strains of the virus.

Download Full-text

Isolation of Tibet Orbivirus from Culicoides jacobsoni (Diptera, Ceratopogonidae) in China

Parasites & Vectors ◽

10.1186/s13071-021-04899-9 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Ying Liang Duan ◽

Zhen Xing Yang ◽

Glenn Bellis ◽

Le Li

Keyword(s):

Bluetongue Virus ◽

Yunnan Province ◽

Virus Isolation ◽

Economic Importance ◽

Western China ◽

Pacific Region ◽

Cattle Farm ◽

Biting Midges ◽

Qpcr Analysis ◽

The Pacific

Abstract Background Tibet Orbivirus (TIBOV) is a recently discovered Orbivirus known to infect cattle, Asian buffalo and goats in south-western China. It was first isolated from mosquitoes and subsequently from biting midges (Culicoides spp.) in Yunnan, China, indicating that it is an arbovirus. Little is known of its potential to cause disease, but the economic importance of related viruses promoted an investigation of potential Culicoides spp. vectors of TIBOV. Methods Biting midges were collected approximately once per week between May and December 2020, at a cattle farm in Wulong village, Shizong County, Yunnan Province, China. Approximately 3000 specimens of nine species were subsequently used in attempts to isolate virus, and a further 2000 specimens of six species were tested for the presence of bluetongue virus (BTV) and TIBOV using a RT-qPCR test. Results Virus isolation attempts resulted in the isolation of three viruses. One isolate from a pool of Culicoidesjacobsoni was identified as TIBOV, while the other two viruses from C.orientalis and C.tainanus remain unidentified but are not BTV or TIBOV. RT-qPCR analysis did not detect BTV in any specimens, but a single pool containing five specimens of C. jacobsoni and another containing five specimens of C. tainanus produced PCR quantification cycle (Cq) values of around 28 that may indicate infection with TIBOV. Conclusions The isolation of TIBOV from C. jacobsoni satisfies one criterion required to prove its status as a vector of this virus. This isolation is supported by a low Cq value produced from a different pool of this species in the RT-qPCR test. The low Cq value obtained from a pool of C. tainanus suggests that this species may also be able to satisfy this criterion. Both of these species are widespread throughout Asia, with C. jacobsoni extending into the Pacific region, which raises the possibility that TIBOV may be more widespread than is currently known. Graphical abstract

Download Full-text

Influenza Virus Usurps an Interferon-Induced Translational Program to Promote Viral Replication

Proceedings ◽

10.3390/proceedings2020050134 ◽

2020 ◽

Vol 50 (1) ◽

pp. 134

Author(s):

Mitchell P. Ledwith ◽

Vy Tran ◽

Thiprampai Thamamongood ◽

Christina A. Higgins ◽

Shashank Tripathi ◽

...

Keyword(s):

Gene Expression ◽

Influenza Virus ◽

Viral Replication ◽

Rna Binding ◽

Viral Gene Expression ◽

Viral Gene ◽

Translational Efficiency ◽

A Genome ◽

Cellular Mrnas ◽

Stimulation Of

Hosts mount prudently tuned responses to viral infection in an attempt to block nearly every step of the replication cycle. Viruses must adapt to replicate in this hostile antiviral cellular state. Interferon stimulation or pathogen challenge robustly induces expression of IFIT (interferon-induced proteins with tetratricopeptide repeats) proteins. IFITs are a family of proteins that bind RNA and play antiviral roles during infection. Thus, we were surprised to identify the IFIT family as top candidate proviral host factors for influenza A virus (IAV) in a genome-wide CRISPR–Cas9 knockout screen. We validated the proviral activity of IFIT2 by showing that IFIT2-deficient cells support lower levels of IAV replication and exhibit defects in viral gene expression. The molecular functions of IFIT2, let alone how they are used by influenza virus, are unknown. Using CLIP-seq, we showed that IFIT2 binds directly to viral and cellular mRNAs in AU-rich regions largely in the 3’UTR, with a preference for a subset of interferon-stimulated mRNAs. IFIT2 also associates with actively translating ribosomes in infected cells to facilitate the translation of viral messages. IFIT2-responsive elements from an IAV mRNA were sufficient to confer translational enhancement to exogenous transcripts in cis. Conversely, mutation of these elements or the use of an IFIT2 RNA-binding mutant ablated stimulation of viral gene expression. Together, these data link the RNA-binding capability of IFIT2 to changes in translational efficiency of target viral mRNAs and the stimulation of viral replication. They establish a model for the normal function of IFIT2 as an antiviral protein affecting the post-transcriptional fate of cellular mRNAs and explain how influenza virus repurposes IFIT2 to support viral replication. Our work highlights a new node for the regulation of translation during interferon responses and highlights how canonical antiviral responses may be repurposed to support viral replication.

Download Full-text

Distribution of protein variation in skipjack tuna (Katsumonus pelamis) from the central and south-west Pacific

Marine and Freshwater Research ◽

10.1071/mf9830231 ◽

1983 ◽

Vol 34 (2) ◽

pp. 231 ◽

Cited By ~ 25

Author(s):

BJ Richardson

Keyword(s):

Isolation By Distance ◽

Low Frequency ◽

Frequency Variation ◽

Skipjack Tuna ◽

Average Heterozygosity ◽

Gene Frequencies ◽

Protein Variation ◽

Guanine Deaminase ◽

Distance Model ◽

East West

Forty-two loci were electrophoretically surveyed for protein variation in the skipjack tuna. A new polymorphism in guanine deaminase was found as well as low-frequency variation in glucosephosphate isomerase and adenosine deaminase. Average heterozygosity for the species was 0 032. The gene frequencies at four variable loci for 70 sample sets, each of approximately 100 animals, collected at locations throughout the South Pacific Commission region, are given. East-west clines in allele frequencies for carboxylesterase and guanine deaminase occur across the study area. There is also within-area heterogeneity in allele frequency at these loci. Previously proposed discrete-stock models and a new isolation-by-distance model for the population structure of skipjack tuna are examined in the light of the genetic data.

Download Full-text

PCR-based reverse genetics strategy for bluetongue virus recovery

Virology Journal ◽

10.1186/s12985-019-1261-2 ◽

2019 ◽

Vol 16 (1) ◽

Author(s):

Qingyuan Xu ◽

Jinying Ge ◽

Maolin Li ◽

Encheng Sun ◽

Yawei Zhou ◽

...

Keyword(s):

Bluetongue Virus ◽

Reverse Genetics ◽

Target Genes ◽

Insect Vector ◽

In Vitro Synthesis ◽

A Genome ◽

Pcr Products ◽

Helper Plasmids ◽

Virus Recovery

Abstract Background Bluetongue virus (BTV), an emerging insect vector mediated pathogen affecting both wild ruminants and livestock, has a genome consisting of 10 linear double-stranded RNA genome segments. BTV has a severe economic impact on agriculture in many parts of the world. Current reverse genetics (RG) strategy to rescue BTV mainly rely on in vitro synthesis of RNA transcripts from cloned complimentary DNA (cDNA) corresponding to viral genome segments with the aid of helper plasmids. RNA synthesis is a laborious job which is further complicated with a need for expensive reagents and a meticulous operational procedure. Additionally, the target genes must be cloned into a specific vector to prepare templates for RNA transcription. Result In this study, we have developed a PCR based BTV RG system with easy two-step transfection. Viable viruses were recovered following a first transfection with the seven helper plasmids and a second transfection with the 10 PCR products on the BSR cells. Further, recovered viruses were characterized with indirect immunofluorescence assays (IFA) and gene sequencing. And the proliferation properties of these viruses were also compared with wild type BTV. Interestingly, we have identified that viruses containing the segment 2 of the genome from reassortant BTV, grew slightly slower than the others. Conclusion In this study, a convenient PCR based RG platform for BTV is established, and this strategy could be an effective alternative to the original available BTV rescue methods. Furthermore, this RG strategy is likely applicable for other Orbiviruses.

Download Full-text