| Mosquito-borne diseases cause serious mortality and morbidity in humans, and pose significant threats to public health. Recent years, there has been new outbreaks of mosquito-borne diseases (such as zika virus) around the world. Vector control is the primary method for controling and preventing mosquito-borne diseases. The widely use of pesticide had resulted in the emergence and spread of resistance in mosquito populations. There is urgent needs for effective prevention and vector control strategies and tools. Only female mosquitoes are responsible for blood sucking and disease transmission. Research and develop new pesticide targeting female reproductive potential could be an efficient way for mosquito population suppression and mosquito-borne disease prevention. This study is designed to illustrate the molecular mechanisms involved in mosquito blood meal processes and reproductive events, which is crucial for developing innovative vector control strategies.PSMB1 was found to be expressed differently in the development stages of Culex pipiens pollens, which was 28-fold (*P<0.05) and 9.5-fold (* P<0.05) higher in pupa stage than in male and female mosquitoes, respectively. Western blot analysis showed that PSMB1 was not expressed in pupa, but dramatically increased in 3 d PE female mosquitoes, which indicated that PSMB1 may have important physiological functions related to female mosquito growth and development. The predicted PSMB1 molecular size is about 24.88 KDa, while the western blot detected protein is about 35 KDa. Analysis showed that after de-glycosylation, the molecular weight of PSMB1 is about 30 KDa, indicating that the presence of glycosylation in mosquito PSMB1.To investigate the role of PSMB1 in female mosquitoes, Western blot was used to detected the expressing level of PSMB1 in head, foot, wings, chest and abdomen we found that it expressed mainly in the chest and abdomen, suggesting that it has tissue specificity. Meanwhile, real-time quantitative PCR was used to detect the expression level of PSMB1 in female mosquito post blood meal (PBM). We found that the expression of PSMB1 rising to the peak at 36h PBM, decreased at 48h PBM, suggesting that the tissue-specific PSMB1 involved in ovarian development of female mosquitoes.To further investigate the role of PSMB1 in the regulation of blood-sucking and reproductive, microinjection was used to delivery PSMB1 dsRNA to female mosquito. PSMB1 interference could significantly reduced the oviposition rate (*** P<0.001), number of eggs (*** P<0.001) and larval hatching rate (*** P<0.001). We pulled out of the female mosquito ovary and found that WT group’s ovaries have neat edges, while PSMB1 knockout group’s ovaries are deformed, which might be the direct cause of affected female reproduction. After PSMB1 interference, we examined the expression levels of other proteasome subunits, PSMB2, PSMB3, PSMB6 are found to be increased after PSMBl knockdown (*** P<0.001,* P<0.05), which indicated that PSMB1 and other proteasome subunits may play a cooperative regulatory role in female mosquito reproduction.Summary, we found that proteasome subunit was only expressed at female abdomen and dsRNA based RNA interference targeting proteasome subunit resulted in reduced fertility in mosquitoes, suggesting that proteasome subunits play important roles in female reproduction. We anticipated that new pesticide target PSMB1 will reach population suppression by decreasing female fertility and the knowledge from this study will greatly facilitate the development of innovative strategies and tools for vector control management and help with vector-borne disease elimination. |
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