Induction by alkaloids and phenobarbital of Family 4 Cytochrome P450s in Drosophila : evidence for involvement in host plant utilization

Abstract

In vertebrates, cytochrome P450s of the CYP2 and CYP3 families play a dominant role in drug metabolism, while in insects members of the CYP6 and CYP28 families have been implicated in metabolism of insecticides and toxic natural plant compounds. A degenerate 3' RACE strategy resulted in the identification of fifteen novel P450s from an alkaloid-resistant species of Drosophila. The strong (17.4-fold) and highly specific induction of a single gene (CYP4D10) by the toxic isoquinoline alkaloids of a commonly utilized host-plant (saguaro cactus) provides the first indication that members of the CYP4 family in insects may play an important role in the maintenance of specific insect-host plant relationships. Strong barbiturate inducibility of CYP4D10 and two other D. mettleri P450 sequences of the CYP4 family was also observed, suggesting a pattern of xenobiotic responsiveness more similar to those of several vertebrate drug-metabolizing enzymes than to putative vertebrate CYP4 homologs.

How do slugs cope with toxic alkaloids?

“…In most animals, the inducible microsomal mixed function oxidase (MFO) system, including cytochrome P-450, is the enzymatic battery responsible for the detoxification of plant allelochemicals, environmental pollutants and other toxins (Danielson et al 1998;Elmamlouk et al 1974;Freeland & Janzen 1974;Jewell & Winston 1989;Smith, 1992). The results of induction experiments (Table 2) could be explained by the involvement of MFO in alkaloid tolerance in A. lusitanicus.…”

Atrazine induction of a family 4 cytochrome P450 gene in Chironomus tentans (Diptera: Chironomidae)

“…Family 4 P450 genes have been identified in numerous insect species, including Anopheles albimanus (Rodrigues and Prough, 1991), Manduca sexta (Snyder et al, 1995), Drosophila melanogaster (Danielson et al, 1998), Diabrotica virgifera virgifera (Scharf et al, 2001) and Musca domestica (Rodrigues and Prough, 1991). Family 4 P450 genes are increasingly being identified as important in conferring resistance to insecticides and other environmental chemicals, and have also been implicated in toxin metabolism (Rodrigues and Prough, 1991).…”

The plastic response of Manduca sexta to host and non-host plants

“…Although four of these P450s were not characterized further, three belong to the CYP4 clan; this clan plays an important role in biosynthesizing hormones and pheromones as well as in metabolizing plant toxins such as isoquinoline alkaloids (Danielson et al, 1998). Seven P450s belong to the CYP3 clan, members of which have been shown to metabolize a broad spectrum of plant compounds such as sesquiterpenes, flavonoids, and insecticides (Feyereisen, 2006;Hung, 1997).…”