EFFECT ON HEARTBEAT OF Drosophila melanogaster OF MUTATIONS IN THE CALCIUM CHANNEL ENCODING cacophony GENE AND ITS INTERACTION WITH THE RNA HELICASE MUTANT malelessnapts

There is a lack of information concerning the genetics of heart disease, especially of those due to aberrant pacemaker activity. Drosophila melanogaster is an ideal candidate for research in this area because of its suitability to genetic manipulation and its accessible genetic database. What is most compelling, however, is that the genesis of heartbeat is Drosophila is strikingly similar to that in many other organisms, including mammals. The myogenic heart ofDrosophiIa melanogaster is stimulated to contract by a caudal pacemaker, which is regulated by ion channel interactions. A voltage-gated calcium channel of PIQ- or N-type is implicated in the pacemaker by pharmacological studies. The voltage-gated calcium channel a, subunit encoding gene in Drosophila, cacophony (cac), was identified as a candidate for this role. After examining heartbeat of the cac alleles cacS and cacfi2 I report that they have increased heart rates and rhythmicities, potentially due to altered inactivation of the calcium channels they encode affecting pacemaking. The gene with which the RNA helicase mutant no action potentialremperflrure-sens'r'v