Nannan Liu, William R Reid and Lee Zhang
Posters: J Proteomics Bioinform
A large number of studies have shown that multiple genes may be responsible for insecticide resistance and differential gene expression has been observed in resistant mosquitoes. To better understand the genetic variation in insecticide resistant mosquitoes Culex quinquefasciatus and gain valuable insights into the gene/proteins interaction and complex regulation system involved in the development of insecticide resistance, we conducted a whole transcriptome analysis of Culex mosquitoes following permethrin selection. We investigate the gene expression profiles between a field strain of Culex quinquefasciatus, HAmCqG0, having a low level (10-fold) of permethrin resistance, and its 8th generation permethrin-selected progeny, HAmCqG8, exhibiting a ~2700-fold high level of resistance using a whole-transcriptome sequencing approach. a total of 367 and 3982 genes found to be up- and down-regulated, respectively, in HAmCqG8, indicating that multiple genes are involved in response to permethrin selection. However, a similar overall cumulative gene expression abundance was identified between up- and down-regulated genes in HAmCqG8 mosquitoes following permethrin selection, suggesting a homeostatic response to insecticides through a balancing of the up- and down-regulation of the genes. While structural and/or cuticular structural functions were the only two enriched GO terms for down-regulated genes, the enriched GO terms obtained for the up-regulated genes occurred primarily among the catalytic and metabolic functions where they represented three functional categories: electron carrier activity, binding, and catalytic activity. Interestingly, the functional GO terms in these three functional categories were overwhelmingly overrepresented in P450s and proteases/serine proteases. The important role played by P450s in the development of insecticide resistance has been extensively studied but the function of proteases/serine proteases in resistance is less well understood. Hence, the characterization of the functions of these proteins, including their digestive, catalytic and proteinase activities; regulation of signaling transduction and protein trafficking, immunity and storage; and their precise function in the development of insecticide resistance in mosquitoes will provide new insights into how genes/proteins are interconnected and regulated in resistance.