The Anopheles gambiae detoxification chip: A highly specific microarray to study metabolic-based insecticide resistance in malaria vectors

Abstract

Metabolic pathways play an important role in insecticide resistance, but the full spectra of the genes involved in resistance has not been established. We constructed a microarray containing unique fragments from 230 Anopheles gambiae genes putatively involved in insecticide metabolism [cytochrome P450s (P450s), GSTs, and carboxylesterases and redox genes, partners of the P450 oxidative metabolic complex, and various controls]. We used this detox chip to monitor the expression of the detoxifying genes in insecticide resistant and susceptible An. gambiae laboratory strains. Five genes were strongly up-regulated in the dichlorodiphenyltrichloroethane-resistant strain ZAN͞U. These genes included the GST GSTE2, which has previously been implicated in dichlorodiphenyltrichloroethane resistance, two P450s, and two peroxidase genes. GSTE2 was also elevated in the pyrethroidresistant RSP strain. In addition, the P450 CYP325A3, belonging to a class not previously associated with insecticide resistance, was expressed at statistically higher levels in this strain. The applications of this detox chip and its potential contribution to malaria vector insecticide resistance management programs are discussed.mosquito ͉ cytochrome P450 ͉ GST ͉ carboxylesterase

Identifying genomic changes associated with insecticide resistance in the dengue mosquito Aedes aegypti by deep targeted sequencing

“…Afterward, the development of mosquito DNA microarrays allowed screening for resistance genes based on their differential transcription, leading to the identification of detoxification genes conferring resistance (David et al 2005Strode et al 2008;Vontas et al 2010;Edi et al 2014). However, these screenings focused on differential transcription while genomic changes such as CNVs and polymorphisms were neglected.…”

Xenobiotic response in Drosophila melanogaster: Sex dependence of P450 and GST gene induction

“…In Drosophila this technique has been used to identify responses to chemical stressors such as paraquat, H 2 O 2 and tunicamycin (Zou et al, 2000;Girardot et al, 2004). Similarly, DNA microarrays have been used to detect genes that are constitutively overexpressed in insecticide-resistant strains from Drosophila and mosquitoes obtained from the fi eld or selected further in the laboratory (Daborn et al, 2002;David et al, 2005;Le Goff et al, 2003;Pedra et al, 2004;Vontas et al, 2005). The design of microarrays that selectively represent all members of the detoxifi cation gene families and appropriate controls genes can provide a useful tool to identify inducible genes.…”

Genomic resources for invertebrate vectors of human pathogens, and the role of VectorBase

“…In addition, the availability of the genome sequence facilitates the development of high-throughput genome wide technologies such as high density expression micro-array, genome tiling array, or chipchip methodology. David et al (2005), for example, developed the first micro-array to study insecticide resistance in malaria vectors. More recently, Vontas et al (2007) monitored gene expression in insecticide resistant and susceptible strains of A. stephensi and identify a small number of genes putatively differentially expressed between the strains.…”

“…A better understanding of the biology of the vector can lead to a faster identification of new targets and ultimately new control measures. For example, David et al (2005) used the A. gambiae annotations and expression profiling using micro-arrays to identify genes involved in insecticide resistance. A potential list of 230 genes was reduced to just five that were highly regulated in insecticide resistant mosquito strains.…”