Peptidoglycan Recognition Protein Is Involved In Immune Responses Against Bacteria In Mosquito Aedes Aegypti

The yellow fever mosquito Aedes aegypti transmits numerous viral arthropod-borne viruses,such as plasmodium,dengue virus,Zika virus and so on,which are extremely damaging to people's health.Intense researches of the mosquito immune system to fight against pathogens play an important role in media insect control.Peptidoglycan recognition protein serves a vital purpose in defense responses of many organisms.This study is working on the functions of peptidoglycan recognition protein LC(AaPGRP-LC)during bacterial infection response in Aedes aegypti.1.Quantitative real-time PCR(qPCR)was used to measure the mRNA abundance of antimicrobial peptides(AMPs)genes in mosquitos after bacteria Enterobacter cloacae infection at different time points.E.cloacae could increase the transcripts levels of genes of AMPs in Ae.aegypti after 6 h post infection.Thus the transcriptional expressions of many essential AMP genes are response to bacterial infection.2.We reduced the expression level of PGRP-LC by RNA interference(RNAi)and evaluated the expression profile of immune-related genes by qPCR.After depletion of AaPGRP-LC,the transcription levels of genes of AMPs were significantly decreased during bacterial infection.These results indicate that PGRP-LC modulates the transcripts levels of AMPs genes.Besides,the expression level of immune genes involved in Toll and IMD pathways were both down-regulated after RNAi of AaPGRP-LC.These results demonstrate that AaPGRP-LC is involved in the regulation of IMD pathway,and may also regulate the Toll pathway.3.Prokaryotic expression system was used for expression and purification of AaPGRP-LC.Furthermore,we tested the quality of the purified recombinant protein by Western blotting.Recombinant protein AaPGRP-LC was purified and we got a clear and single target band after Western blotting.In addition,the obtained recombinant PGRP-LC can be used in the follow-up study.