Bluetongue virus (BTV) causes Bluetongue (BT) of ruminants vectored by culicoides midges. It is also a classic model for studying the release mechanism of non-enveloped virus. This review begins with the infection and assembly of BTV, then summarizes the advances of different ways of releasing BTV. This includes BTV-induced autophagy and the release as extracellular vesicles via multivesicular bodies, BTV-induced apoptosis and the lytic release, as well as different pathways of release through budding via plasma membrane. The regulatory mechanisms of NS3 which is a key non-structural protein during the release of BTV are also discussed, providing a basis for further understanding the molecular mechanisms underpinning the infection, proliferation and release of BTV.
Animals ; Bluetongue ; Bluetongue virus ; Ceratopogonidae ; Sheep ; Viral Nonstructural Proteins

OBJECTIVETo isolate viruses from mosquitoes in the south of Xinjiang and identify these viruses primarily.

METHODSA total of 13 491 mosquitoes were collected in the south of Xinjiang from Jul to Aug, 2005. These mosquitoes were divided into 130 groups and grinded respectively. The supernates were inoculated in C6/36 and Vero cells. Viruses isolated were detected, the genomic nucleic types by electrophoresis of viral genomes and the morphologies observed under electronmicroscope.

RESULTSAll 42 viruses were isolated, which caused CPEs on C6/36 but not on Vero cells. 27 viruses showed similar genomic profiles with 12 dsRNA segments. 1 virus displayed genomic profile with 10 dsRNA segments. 5 viruses took on similar genomic profiles with about 4 kbp DNA band. 9 viruses did not get any taxonomy information. Electromicroscopic pictures of these viruses revealed that above four types of viruses had distinguished morphologies indicating different virus species.

CONCLUSIONThere should be several virus species in the mosquitoes in the south of Xinjiang. dsRNA virus with 12 genomic segments should play analysis a predominant role in the south of Xinjiang.

Animals ; Bluetongue virus ; classification ; genetics ; isolation & purification ; Cercopithecus aethiops ; China ; Culicidae ; virology ; Dengue Virus ; classification ; genetics ; isolation & purification ; Genome, Viral ; Insect Viruses ; classification ; genetics ; isolation & purification ; RNA, Double-Stranded ; genetics ; RNA, Viral ; genetics ; Reassortant Viruses ; genetics ; Sequence Analysis, DNA ; Vero Cells

OBJECTIVETo study the death mode of human hepatocellular carcinoma Hep-3B cells and human lung adenocarcinoma A549 cells induced by bluetongue virus strain HbC3 (BTV-HbC3) and the mechanism of its action.

METHODSBTV-HbC3 was used to infect the tumor cells, and the cytopathic effects (CPE) was observed. TUNEL staining was used to detect the apoptosis of tumor cells induced by BTV-HbC3. The changes of endoplasmic reticulum and nuclei treated with BTV-HbC3 were further examined by laser scanning confocal microscopy. The activities of caspase-3/7, caspase-8 and caspase-9 were determined by fluorescence analysis.

RESULTSHep-3B cells were sensitive to BTV-HbC3. Lots of early apoptotic cells were found by TUNEL staining. The laser scanning confocal microscopic examination showed characteristics of apoptosis, such as pyknotic nuclei, margination of nuclear chromatin and vacuolization of endoplasmic reticulumin in Hep-3B cells exposed to BTV-HbC3. The activity of caspase-3/7 was increased, but the activity changes of caspase-8 and caspase-9 were not found. A549 cells were sensitive to BTV-HbC3 too. But no apoptotic cells were observed by TUNEL staining. The results of laser scanning confocal microscopy showed marked vacuolization of endoplasmic reticulum, but chromatin margination was not found after A549 cells was exposed to BTV-HbC3. The activity of caspase-3/7 and caspase-9 was increased, but the activity of caspase-8 was not changed.

CONCLUSIONBTV-HbC3 induces apoptosis of Hep-3B tumor cells mainly through endoplasmic reticulum signal transduction pathway, and the features of cell death in A549 cells could be described as paraptosis.

Adenocarcinoma ; metabolism ; pathology ; virology ; Apoptosis ; Bluetongue virus ; pathogenicity ; physiology ; Carcinoma, Hepatocellular ; metabolism ; pathology ; virology ; Caspase 3 ; metabolism ; Caspase 8 ; metabolism ; Caspase 9 ; metabolism ; Cell Line, Tumor ; Cell Nucleus ; pathology ; Endoplasmic Reticulum ; pathology ; Humans ; Liver Neoplasms ; metabolism ; pathology ; virology ; Lung Neoplasms ; metabolism ; pathology ; virology ; Oncolytic Viruses ; pathogenicity ; physiology ; Signal Transduction