Project description:Background The generalist dipteran pupal parasitoid Nasonia vitripennis injects 79 venom peptides into the host before egg laying. This venom induces several important changes in the host, including developmental arrest, immunosuppression, and alterations to normal metabolism. It is hoped that diverse and potent bioactivities of N. vitripennis venom provide an opportunity for the design of novel acting drugs. However, currently very little is known about the individual functions of N. vitripennis venom peptides and less than half can be bioinformatically annotated. The paucity of annotation information complicates the design of studies that seek to better understand the potential mechanisms underlying the envenomation response. Although the RNA interference system of N. vitripennis provides an opportunity to functionally characterise venom encoding genes, with 79 candidates this represents a daunting task. For this reason we were interested in determining the expression levels of venom encoding genes in the venom gland, such that this information could be used to rank candidate venoms. To do this we carried out deep sequencing of the transcriptome of the venom gland and neighbouring ovary tissue and used RNA-seq to measure expression from the 79 venom encoding genes. The generation of a specific venom gland transcriptome dataset also provides further opportunities to investigate novel features of this highly specialised organ. Results High throughput sequencing and RNA-seq revealed that the highest expressed venom encoding gene in the venom gland was a serine protease called Nasvi2EG007167, which has previously been implicated in the apoptotic activity of N. vitripennis venom. As expected the RNA-seq confirmed that the N. vitripennis venom encoding genes are almost exclusively expressed in the venom gland relative to the neighbouring ovary tissue. Novel peptides appear to perform key roles in N. vitripennis venom function as only four of the highest 15 expressed venom encoding genes are bioinformatically annotationed. The high throughput sequencing data also provided evidence for the existence of an additional 471 novel genes in the Nasonia genome that are expressed in the venom gland and ovary. Finally, metagenomic analysis of venom gland transcripts identified viral transcripts that may play an important part in the N. vitripennis venom function. Conclusions The expression level information provided here for the 79 venom encoding genes provides an unbiased dataset that can be used by the N. vitripennis community to identify high value candidates for further functional characterisation. These candidates represent bioactive peptides that have value in drug development pipelines.

Project description:Snake venoms have evolved in a few families of Caenophidae, and their toxins have been fine-tuned over the evolutive process into highly effective biochemical weapons with a particular role as a trophic adaptation. However, there are many outstanding questions on how venom contributes to the success of venomous species and their adaptation to different environments. Here we analyze the venoms from sympatric and generalist specimens of B. hyoprora, B. taeniatus, B. b. smaragdinus, B. brazili, and B. atrox collected in the wild of Alto Juruá region at the Amazon Forest aiming to understand whether the venom composition could be a driver or influence the arboreal habitats of B. taeniatus and B. b. smaragdinus, or the successful dispersion of B. atrox across the Amazon Forest. Venom composition and the primary sequences of toxin isoforms were characterized by venom gland transcriptomics followed by proteomics. The venom composition of the five species conserved the same protein families present in venoms of Bothropoid snakes but with remarkable differences in the chromatographic profiles and in the relative amount of each toxin group: CTLs were the most abundant in the venoms of B. taeniatus (31.6%), B. b. smaragdinus (33.0%), and B. atrox (32.0%) and SVMPs and PLA2s dominated in venoms of B. hyoprora (23.7% and 20.2%) and B. brazili (20.2% and 20.4%). Some peculiarities were also observed: B. hyoprora venom was the least complex, conserving important isoforms shared with B. atrox venom; the presence of one cluster of SVSPs exclusive to B. brazili venom isoforms; and the presence of the K49-PLA2 homologs only in B. b. smaragdinus and particularly in B. brazili venoms. The SVMP, SVSP, and PLA2 enzyme activities were consistent with the abundance and type of isoforms present in the venoms. B. hyoprora, B. taeniatus, B. b. smaragdinus, and B. atrox venoms presented low lethality to small rodents, while B. brazili venom was the most lethal. Concluding, differences were evidenced between the venoms of B. taeniatus and B. b. smaragdinus arboreal species, while B. b. smaragdinus shared a venom with a similar composition to B. atrox venom, mostly terrestrial. Considering the role of venom toxicity in species' success for adaptation in different areas, B. atrox is the most adapted in the whole Amazonian territory and presented the least lethal venom, while the venom of B. brazili was the most lethal despite its small distribution in the same area. Therefore, our data suggest that the selection of venom composition may not influence the success or behavior of snake species. In this way, other biotic or abiotic factors influence their foraging status or their dispersal in different ecological niches.

			Action	DRS
	SRR26583170_1.fastq.gz	Fastqsanger.gz
	SRR26583170_2.fastq.gz	Fastqsanger.gz

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