RESUMO
The insect juvenile hormone receptor is a basic helix-loop-helix (bHLH), Per-Arnt-Sim (PAS) domain protein, a novel type of hormone receptor. In higher flies like Drosophila, the ancestral receptor germ cell-expressed (gce) gene has duplicated to yield the paralog Methoprene-tolerant (Met). These paralogous receptors share redundant function during development but play unique roles in adults. Some aspects of JH function apparently require one receptor or the other. To provide a foundation for studying JH receptor function, we have recapitulated endogenous JH receptor expression with single cell resolution. Using Bacteria Artificial Chromosome (BAC) recombineering and a transgenic knock-in, we have generated a spatiotemporal expressional atlas of Met and gce throughout development. We demonstrate JH receptor expression in known JH target tissues, in which temporal expression corresponds with periods of hormone sensitivity. Larval expression largely supports the notion of functional redundancy. Furthermore, we provide the neuroanatomical distribution of JH receptors in both the larval and adult central nervous system, which will serve as a platform for future studies regarding JH action on insect behavior.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Proteínas de Drosophila/genética , Drosophila/genética , Regulação da Expressão Gênica no Desenvolvimento , Hormônios Juvenis/metabolismo , Fatores de Transcrição/genética , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Drosophila/crescimento & desenvolvimento , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Larva/metabolismo , Fatores de Transcrição/metabolismoRESUMO
Perception of the earth's gravitational force is essential for most forms of animal life. However, little is known of the molecular mechanisms and neuronal circuitry underlying gravitational responses. A forward genetic screen using Drosophila melanogaster that provides insight into these characteristics is described here. Vertical choice mazes combined with additional behavioral assays were used to identify mutants specifically affected in gravitaxic responses. Twenty-three mutants were selected for molecular analysis. As a result, 18 candidate genes are now implicated in the gravitaxic behavior of flies. Many of these genes have orthologs across the animal kingdom, while some are more specific to Drosophila and invertebrates. One gene (yuri) located close to a known locus for gravitaxis has been the subject of more extensive analysis including confirmation by transgenic rescue.
