Analysis of molecular and physiological pathways regulating social behavior in honey bees: elucidating the role of Kr-h1 and cGMP
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Date
2009-12-04
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Abstract
Kruppel homolog 1 (Kr-h1) is a zinc finger transcription factor whose brain expression levels are associated with foraging behavior and are regulated by queen mandibular pheromone (QMP) in honey bees. We used behavioral, physiological, and genomic approaches to investigate the factors which regulate expression of Kr-h1 in honey bees, and employed a comparative genomics approach to begin to characterize the molecular function of this protein. We demonstrated that brain expression of Kr-h1 is associated with permanent physiological changes that occur during behavioral maturation from nursing to foraging, rather than the acute expression of foraging behavior. Furthermore, we demonstrated that Kr-h1 expression is modulated by cGMP, a key regulator of behavior maturation, and identified a potential cGMP response element in the promoter of Kr-h1. We then characterized the interactions between cGMP and QMP. cGMP inhibited behavioral and physiological responses to QMP, and partially inhibited expression changes of QMP-responsive genes in the brain. Treatment with these factors specifically altered expression of genes associated with GTPase regulator activity, phototransduction, and positive regulation of antibacterial peptide biosynthetic process. However, cGMP did not affect the expression of AmOr11, an odorant receptor specific for a major chemical component of QMP, suggesting that cGMP might work centrally rather than peripherally to modulate the response to QMP. Finally, we elucidated changes in gene expression that resulted from the absence of Kr-h1 expression during D. melanogaster development and discovered an associated motif in the promoter of the majority of the significantly expressed genes, which may mediate the effects of Kr-h1. Further analysis, however, showed that this motif is unlikely to be biologically relevant. These studies have demonstrated the ability of physiological factors to modulate responsiveness to social cues, and provided further information about the role of Kr-h1 in regulating behavior in bees.
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Kr-h1, honey bee, behavior, genomics, pheromone, chemical ecology, genetics
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PhD
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Genetics
