Functional characterization of CYP4G11—a highly conserved enzyme in the western honey bee Apis mellifera

Abstract

Determining the functionality of CYP4G11, the only CYP4G in the genome of the western honey bee Apis mellifera, can provide insight into its reduced CYP4 inventory. Toward this objective, CYP4G11 transcripts were quantified, and CYP4G11 was expressed as a fusion protein with housefly CPR in Sf9 cells. Transcript levels varied with age, task, and tissue type in a manner consistent with the need for cuticular hydrocarbon production to prevent desiccation or with comb wax production. Young larvae, with minimal need for desiccation protection, expressed CYP4G11 at very low levels. Higher levels were observed in nurses, and even higher levels in wax producers and foragers, the latter of which risk desiccation upon leaving the hive. Recombinant CYP4G11 readily converted octadecanal to n-heptadecane in a time-dependent manner, demonstrating its functions as an oxidative decarbonylase. CYP4G11 expression levels are high in antennae; heterologously expressed CYP4G11 converted tetradecanal to n-tridecane, demonstrating that it metabolizes shorter-chain aldehydes. Together, these findings confirm the involvement of CYP4G11 in cuticular hydrocarbon production and suggest a possible role in clearing pheromonal and phytochemical compounds from antennae. This possible dual functionality of CYP4G11, i.e., cuticular hydrocarbon and comb wax production and antennal odorant clearance, may explain how honey bees function with a reduced CYP4G inventory.

Involvement of integument‐rich CYP4G19 in hydrocarbon biosynthesis and cuticular penetration resistance in Blattella germanica (L.)

“…The B. germanica genome contains only one CYP4G gene, and we have found that it plays a role in hydrocarbon production. Likewise, Acyrthosiphon pisum CYP4G51 and Apis mellifera CYP4G11 , the only CYP4G member in each species, have also been shown to be involved in hydrocarbon biosynthesis . We hypothesize that if only one CYP4G member is found in a given species it would at least participate in hydrocarbon biosynthesis.…”

“…Unlike the B. germanica CYP4G19 that appears to be an abdominal oenocyte‐specific expression, CYP4G11 and CYP4G51 also showed highly abdomen‐independent expression . The expression of CYP4G11 in forager antennae was recently linked to the clearance of pheromonal aldehydes . That is, although CYP4G s are highly conserved in participating in hydrocarbon biosynthesis, the importance of this pathway in different species may confer upon CYP4G s a diversity of biologically important roles.…”

“…Likewise, Acyrthosiphon pisum CYP4G51 and Apis mellifera CYP4G11, the only CYP4G member in each species, have also been shown to be involved in hydrocarbon biosynthesis. 36,38 We hypothesize that if only one CYP4G member is found in a given species it would at least participate in hydrocarbon biosynthesis. Unlike the B. germanica CYP4G19 that appears to be an abdominal oenocyte-specific expression, CYP4G11 and CYP4G51 also showed highly abdomen-independent expression.…”

“…38,59 The expression of CYP4G11 in forager antennae 59 was recently linked to the clearance of pheromonal aldehydes. 36 That is, although CYP4Gs are highly conserved in participating in hydrocarbon biosynthesis, the importance of this pathway in different species may confer upon CYP4Gs a diversity of biologically important roles. The high expression of CYP4G51 and its role in the aphid head remain elusive.…”

“…9,32 The only CYP4G member in B. germanica, CYP4G19, 33 was reported to be overexpressed in a pyrethroid-resistant strain, 34 but no role in insecticide resistance has been attributed to CYP4G19. Several CYP4G genes have been functionally characterized to be involved in the final decarbonylation step of hydrocarbon biosynthesis by baculovirus expression system 9,[35][36][37] or RNAi-based functional studies. 38,39 The insect-specific CYP4G genes are among the rare P450 members with orthologs distributed throughout the Insecta.…”