GENETIC AND DEVELOPMENTAL CHARACTERIZATION OF DMCA1D, A CALCIUM-CHANNEL ALPHA(1) SUBUNIT GENE IN DROSOPHILA-MELANOGASTER

To begin unraveling the functional significance of calcium channel div ersity, we identified mutations in Dmca1D, a Drosophila calcium channe l oct subunit cDNA that we recently cloned. These mutations constitute the l(2)35Fa lethal locus, which we rename Dmca1D. A severe allele, D mca1D(X10), truncates the channel after the IV-S4 transmembrane domain . These mutants die as late embryos because they lack vigorous hatchin g movements. In the weaker allele, Dmca1D(AR66), a cysteine in transme mbrane domain I-S1 is changed to tyrosine. Dmca1D(AR66) embryos hatch but pharate adults have difficulty eclosing. Those that do eclose have difficulty in fluid-filling of the wings. These studies show that thi s member of the calcium channel oc, subunit gene family plays a nonred undant, vital role in larvae and adults.