CALMODULIN POINT MUTATIONS AFFECT DROSOPHILA DEVELOPMENT AND BEHAVIOR

Calmodulin (CAM) is recognized as a major intermediary in intracellula r calcium signaling, but as yet little is known of its role in develop mental and behavioral processes. We have generated and studied mutatio ns to the endogenous Cam gene of Drosophila melanogaster that change s ingle amino acids within the protein coding region. One of these mutat ions produces a striking pupal lethal phenotype involving failure of h ead eversion. Various mutant combinations produce specific patterns of ectopic wing Vein formation or melanotic scabs on the cuticle. Anapha se chromosome bridging is also seen as a maternal effect during the ea rly embryonic nuclear divisions. In addition, specific behavioral defe cts such as poor climbing and flightlessness are detected among these mutants. Comparisons with other Drosophila mutant phenotypes suggests potential CAM targets that may mediate these developmental and behavio ral effects, and analysis of the CAM crystal structure suggests the st ructural consequences of the individual mutations.