| Autor: |
Rezende TMT; Department of Entomology, Instituto Aggeu Magalhães-Fiocruz, Recife 50740-465, PE, Brazil., Menezes HSG; Department of Entomology, Instituto Aggeu Magalhães-Fiocruz, Recife 50740-465, PE, Brazil., Rezende AM; Department of Microbiology, Instituto Aggeu Magalhães-Fiocruz, Recife 50740-465, PE, Brazil., Cavalcanti MP; Department of Microbiology, Instituto Aggeu Magalhães-Fiocruz, Recife 50740-465, PE, Brazil., Silva YMG; Department of Entomology, Instituto Aggeu Magalhães-Fiocruz, Recife 50740-465, PE, Brazil., de-Melo-Neto OP; Department of Microbiology, Instituto Aggeu Magalhães-Fiocruz, Recife 50740-465, PE, Brazil., Romão TP; Department of Entomology, Instituto Aggeu Magalhães-Fiocruz, Recife 50740-465, PE, Brazil., Silva-Filha MHNL; Department of Entomology, Instituto Aggeu Magalhães-Fiocruz, Recife 50740-465, PE, Brazil.; National Institute for Molecular Entomology, Rio de Janeiro 21941-902, RJ, Brazil. |
| Abstrakt: |
Culex quinquefasciatus resistance to the binary (Bin) toxin, the major larvicidal component from Lysinibacillus sphaericus , is associated with mutations in the cqm1 gene, encoding the Bin-toxin receptor. Downregulation of the cqm1 transcript was found in the transcriptome of larvae resistant to the L. sphaericus IAB59 strain, which produces both the Bin toxin and a second binary toxin, Cry48Aa/Cry49Aa. Here, we investigated the transcription profiles of two other mosquito colonies having Bin resistance only. These confirmed the cqm1 downregulation and identified transcripts encoding the enzyme pantetheinase as the most downregulated mRNAs in both resistant colonies. Further quantification of these transcripts reinforced their strong downregulation in Bin-resistant larvae. Multiple genes were found encoding this enzyme in Cx. quinquefasciatus and a recombinant pantetheinase was then expressed in Escherichia coli and Sf 9 cells, with its presence assessed in the midgut brush border membrane of susceptible larvae. The pantetheinase was expressed as a ~70 kDa protein, potentially membrane-bound, which does not seem to be significantly targeted by glycosylation. This is the first pantetheinase characterization in mosquitoes, and its remarkable downregulation might reflect features impacted by co-selection with the Bin-resistant phenotype or potential roles in the Bin-toxin mode of action that deserve to be investigated. |
