title: Cytochrome P450s--Their expression, regulation, and role in insecticide resistance.
abstract: P450s are known to be critical for the detoxification and/or activation of xenobiotics such as drugs and pesticides and overexpression of P450 genes can significantly affect the disposition of xenobiotics in the tissues of organisms, altering their pharmacological/toxicological effects. In insects, P450s play an important role in detoxifying exogenous compounds such as insecticides and plant toxins and their overexpression can result in increased levels of P450 proteins and P450 activities. This has been associated with enhanced metabolic detoxification of insecticides and has been implicated in the development of insecticide resistance in insects. Multiple P450 genes have been found to be co-overexpressed in individual insect species via several constitutive overexpression and induction mechanisms, which in turn are co-responsible for high levels of insecticide resistance. Many studies have also demonstrated that the transcriptional overexpression of P450 genes in resistant insects is regulated by trans and/or cis regulatory genes/factors. Taken together, these earlier findings suggest not only that insecticide resistance is conferred via multi-resistance P450 genes, but also that it is mediated through the interaction of regulatory genes/factors and resistance genes. This chapter reviews our current understanding of how the molecular mechanisms of P450 interaction/gene regulation govern the development of insecticide resistance in insects and our progress along the road to a comprehensive characterization of P450 detoxification-mediated insecticide resistance.
authors.affiliation: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA. Electronic address: liunann@auburn.edu.
authors.forename: Nannan
authors.initials: N
authors.lastname: Liu
authors.affiliation: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA; Department of Entomology, China Agricultural University, Beijing, China.
authors.forename: Youhui
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849, USA.
authors.forename: Ting
authors.initials: T
authors.lastname: Li
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D015870:Gene Expression; D019476:Insect Proteins / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics*; D008958:Models, Molecular; D010574:Pesticide Synergists / Q000494:pharmacology
chemical_list: D019476:Insect Proteins; D010574:Pesticide Synergists; D003577:Cytochrome P-450 Enzyme System
keywords: Cytochrome P450; Homology modeling; Induction; Insecticide resistance; Interaction/regulation