Sex-linked transcription factor involved in a shift of sex-pheromone preference in the silkmoth Bombyx mori

Laboratory of Insect Genetics and Bioscience, Department of Agricultural and Environmental Biology, University of Tokyo, Tokyo 113-8657, Japan.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 11/2011; 108(44):18038-43. DOI: 10.1073/pnas.1107282108
Source: PubMed


In the sex-pheromone communication systems of moths, odorant receptor (Or) specificity as well as higher olfactory information processing in males should be finely tuned to the pheromone of conspecific females. Accordingly, male sex-pheromone preference should have diversified along with the diversification of female sex pheromones; however, the genetic mechanisms that facilitated the diversification of male preference are not well understood. Here, we explored the mechanisms involved in a drastic shift in sex-pheromone preference in the silkmoth Bombyx mori using spli mutants in which the genomic structure of the gene Bmacj6, which encodes a class IV POU domain transcription factor, is disrupted or its expression is repressed. B. mori females secrete an ∼11:1 mixture of bombykol and bombykal. Bombykol alone elicits full male courtship behavior, whereas bombykal alone shows no apparent activity. In the spli mutants, the behavioral responsiveness of males to bombykol was markedly reduced, whereas bombykal alone evoked full courtship behavior. The reduced response of spli males to bombykol was explained by the paucity of bombykol receptors on the male antennae. It was also found that, in the spli males, neurons projecting into the toroid, a compartment in the brain where bombykol receptor neurons normally project, responded strongly to bombykal. The present study highlights a POU domain transcription factor, Bmacj6, which may have caused a shift of sex-pheromone preference in B. mori through Or gene choice and/or axon targeting.

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Available from: Shigehiro Namiki
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    • "Analyses of silkmoths with a null mutation in Bmacj6, a homolog of D. melanogaster abnormal chemosensory jump6 (acj6) that encodes a class IV POU domain transcription factor, have provided insight into the genetic mechanisms that may modify pheromone specificity at the behavioral level in moths (Fujii et al., 2011). In D. melanogaster, the acj6 mutant displays abnormal olfactory behavior (Ayer and Carlson, 1991), and genetic and electrophysiological analyses have suggested that acj6 determines the OR gene choice and axon targeting of ORNs (Clyne et al., 1999; Komiyama et al., 2004). "
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