RESULTS:
1 - 4 of 4 for "Annie Bézier"
Transcriptional dynamics during Heliothis zea nudivirus 1 infection in an ovarian cell line from Helicoverpa zea
Nudiviruses (family Nudiviridae) are double-stranded DNA viruses that infect various insects and crustaceans. Among them Heliothis zea nudivirus 1 (HzNV-1) represents the rare case of a lepidopteran nudivirus inducing a sexual pathology. Studies about molecular pathological dynamics of HzNV-1 or other nudiviruses are scarce. Hence this study aims to provide a transcriptomic profile of HzNV-1 in an ovary-derived cell line of Helicoverpa zea (HZ-AM1) during early (3 6 and 9 h post-infection) and advanced (12 and 24 h post-infection) stages of infection. Total RNA was extracted from both virus- and mock-infected cells and RNA-seq analysis was performed to examine both virus and host transcriptional dynamics. Hierarchical clustering was used to categorize viral genes while differential gene expression analysis was utilized to pinpoint host genes that are significantly affected by the infection. Hierarchical clustering classified the 154 HzNV-1 genes into four temporal phases with early phases mainly involving transcription and replication genes and later phases including genes for virion assembly. In addition a novel viral promoter motif was identified in the upstream region of early-expressed genes. Host gene analysis revealed significant upregulation of heat shock protein genes and downregulation of histone genes. The identification of temporal patterns in viral gene expression enhances the molecular understanding of nudivirus pathology while the identified differentially expressed host genes highlight the key pathways most hijacked by HzNV-1 infection.
ICTV Virus Taxonomy Profile: Nudiviridae
Members of the family Nudiviridae are large dsDNA viruses with distinctive rod-shaped nucleocapsids and circular genomes of 96–232 kbp. Nudiviruses have been identified from a diverse range of insects and crustaceans and are closely related to baculoviruses. This is a summary of the International Committee on Taxonomy of Viruses Report on the taxonomy of the family Nudiviridae which is available at ictv.global/report/nudiviridae.
Qualitative proteomic analysis of Tipula oleracea nudivirus occlusion bodies
Nudiviruses are arthropod-specific large double-stranded circular DNA viruses related to baculoviruses which replicate in the nucleus of the cells they infect. To date six fully sequenced nudiviral genomes are available in databases and the protein profile from nudivirus particles was mainly characterized by PAGE. However only a few direct matches have been completed between genomic and proteomic data with the exception of the major occlusion body protein from Penaeus monodon nudivirus and four nucleocapsid proteins from Helicoverpa zea nudivirus-2. The function of predicted nudiviral proteins is still inferred from what is known from baculoviruses or endogenous nudiviruses (i.e. bracoviruses). Tipula oleracea nudivirus (ToNV) is the causative agent of crane fly nucleopolyhedrosis. Along with Penaeus monodon nudivirus ToNV is the second fully sequenced nudivirus to be described as forming occlusion bodies. The protein profile revealed by Coomassie-stained SDS-PAGE is very similar to those observed for other nudiviruses with five major protein bands of about 75 48 35 25 and 12 kDa. Proteomic analysis using on-line nanoflow liquid chromatography in tandem with high-resolution mass spectrometry revealed that ToNV occlusion bodies are composed of 52 viral proteins the most abundant of which are the functional homologue of baculovirus polyhedrin/granulin and the homologues of three Helicoverpa zea nudivirus-2 predicted proteins: the two virion structural proteins 34K (Hz2V052 the baculovirus capsid protein VP39 homologue) and 11K (Hz2V025) and the hypothetical protein Hz2V079 a newly identified nudivirus core gene product.
Identification of bracovirus particle proteins and analysis of their transcript levels at the stage of virion formation
Polydnaviruses (PDVs) are unique symbiotic viruses associated with parasitic wasps; they replicate only in the calyx cells of a wasp's ovaries and are transferred at oviposition along with the parasitoid egg into the lepidopteran host. The DNA packaged in the viral particles encodes factors that manipulate the host's immune defences and development to benefit the parasitoid. PDVs are found in two subfamilies of ichneumonids (ichnoviruses) and in braconids of the microgastroid complex (bracoviruses). We recently showed that the latter derive from an ancestral nudivirus as 24 nudivirus-related genes were identified in ovaries of two distantly related braconids at the stage of virion formation. Here we present a comprehensive analysis of the viral particle proteins of the Chelonus inanitus bracovirus (CiBV). Proteins of purified CiBV particles were analysed by mass spectrometry and amino acid sequences matched to the existing ovarian-cDNA database. In addition transcript quantities of identified genes were measured by quantitative real-time PCR in female pupae at the onset and peak of virion formation and at corresponding stages in male pupae. This combined approach allowed the identification of 44 CiBV particle proteins: 16 were nudivirus-related three had similarity to ovarian proteins of another braconid 11 had similarity to cellular proteins and 14 had no similarity to known proteins. The transcripts of all of them increased in female but not male pupae. These data confirm the important contribution of nudivirus genes but also indicate the presence of many lineage- or species-specific proteins possibly involved in the parasitoid–host interaction.