Meeting Abstract
Ecdysteroids are synthesized from cholesterol by a conserved group of cytochrome P450 enzymes. In insects, specific P450 ecdysteroidogenic enzymes have been identified and are referred to as ‘Halloween’ genes due to their ‘ghostly’ mutant larval cuticle phenotype. In crabs, the Y-organ (YO) contains the enzymes that produce 20-hydroxyecdysone and is consequently important in molt regulation. We have analyzed crab YO next generation sequencing data from animals where molting has been stimulated using two molt-inducing experimental methodologies—eye stalk ablation (ESA) and multiple limb autonomy (MLA). This data was collected using the blackback land crab, Gecarcinus lateralis, as the YO tissue source. The ESA dataset represented YO mRNA populations from intermolt, early, mid and late premolt. The MLA data represented mRNA populations isolated through these four physiological molt stages, as well as postmolt. In addition, these datasets were also compared to transcriptomes from the fiddler crab, Uca pugilator, built from limb bud tissues undergoing progressive stages of regeneration during the molt cycle following MLA. Analysis of these datasets indicated: 1) Halloween gene homologs of the insect P450 enzymes were identified in both YO libraries; 2) Halloween gene mRNA levels increased over the molt cycle for ESA induced animals; 3) Halloween gene mRNA levels did not increase over the molt cycle for MLA induced animals, i.e, in parallel with increasing circulating hormone titers; 4) Halloween gene homologs were also identified in regenerating limbs. Whether other tissues may be a source of circulating hormone remains to be investigated. Supported by NSF (IOS-1257732).
