Project description:The impact of global climate change on the transmission dynamics of infectious diseases is the subject of extensive debate. The transmission of mosquito-borne viral diseases is particularly complex, with climatic variables directly affecting many parameters associated with the prevalence of disease vectors. While evidence shows that warmer temperatures often decrease the extrinsic incubation period of an arthropod-borne virus (arbovirus), exposure to cooler temperatures often predisposes disease vector mosquitoes to higher infection rates. RNA interference pathways are essential to antiviral immunity in the mosquito; however, few experiments have explored the effects of temperature on the RNAi machinery.
Project description:Transcription profiling of permethrin resistant field mosquito samples of Anopheles funestus from three Southern African populations (Mozambique, Malawi and Zambia) compared to a susceptible lab strain FANG
Project description:How viruses, such as the emerging mosquito-borne Chikungunya virus (CHIKV), express their genomes at high levels despite an enrichment in suboptimal codons remains a puzzling question. By integrating subcellular fractionation and transcriptome-wide analyses of translation in CHIKV-infected human cells, we demonstrate an unanticipated virus-induced reprogramming of the host translation machinery to favor translation of viral RNA over cellular genes featuring optimal codon usage. This reprogramming was specifically apparent at the endoplasmic reticulum (ER), the preferred translation compartment of CHIKV RNA, and it is mediated by the wobble uridine 34 tRNA modification enzyme KIAA1456 whose expression is enhanced upon viral infection. Since KIAA1456 itself is encoded by a CHIKV-like codon usage, infection triggers a positive feed-back loop that ensures efficient virus protein production. Our findings demonstrate an unprecedented interplay of viruses with the host tRNA epitranscriptome to favor viral protein expression.
Project description:The impact of global climate change on the transmission dynamics of infectious diseases is the subject of extensive debate. The transmission of mosquito-borne viral diseases is particularly complex, with climatic variables directly affecting many parameters associated with the prevalence of disease vectors. While evidence shows that warmer temperatures often decrease the extrinsic incubation period of an arthropod-borne virus (arbovirus), exposure to cooler temperatures often predisposes disease vector mosquitoes to higher infection rates. RNA interference pathways are essential to antiviral immunity in the mosquito; however, few experiments have explored the effects of temperature on the RNAi machinery. Total small RNAs (miRNAs, siRNAs, piRNAs, etc.) were isolated and sequenced from the heads of sensor strain Aedes aegypti mosquitoes, or from the whole bodies of CHIKV-infected Aedes albopictus mosquitoes 8 hours post infection. Mosquitoes were grown at 18C or 28C in replicates of 1 (Ae. aegypti) or 3 (Ae. albopictus).
Project description:The Flavivirus genus contains some of the most prevalent vector-borne viruses such as dengue, Zika and yellow fever viruses that cause devastating diseases in humans. However, the insect-specific clade of flaviviruses is restricted to mosquito hosts; albeit they have retained the general features of the genus such as genome structure and replication. The interaction between insect-specific flaviviruses (ISFs) and their mosquito hosts are largely unknown. Pathogenic flaviviruses are known to modulate host-derived microRNAs (miRNAs), a class of non-coding RNAs that are important in controlling gene expression. Alteration in miRNAs may represent changes in host gene expression and provide understanding of virus-host interactions. The role of miRNAs in ISF-mosquito interactions is largely unknown. A recently discovered Australian ISF, Palm Creek virus (PCV), has the ability to suppress medically relevant flaviviruses. Here, we investigated the potential involvement of miRNAs in PCV infection using the model mosquito Aedes aegypti. By combining small RNA sequencing and bioinformatics analysis, differentially expressed miRNAs were determined. Our results indicated that PCV infection hardly affects host miRNAs. Out of 101 reported miRNAs of Ae. aegypti, only aae-miR-2940-5p had significant altered expression over the course of infection. However, further analysis of aae-miR-2940-5p revealed that this miRNA does not have any direct impact on PCV replication in vitro. Thus, the results overall suggest that PCV infection has a limited effect on the mosquito miRNA profile and therefore, they may not play a significant role the PCV- Ae. aegypti interaction.