Genetic and Developmental Characterization of Dmca1D, a Calcium Channel α1 Subunit Gene in Drosophila melanogaster

To begin unraveling the functional significance of calcium channel diversity, we identified mutations in Dmca1D, a Drosophila calcium channel α1 subunit cDNA that we recently cloned. These mutations constitute the l(2)35Fa lethal locus, which we rename Dmca1D. A severe allele, Dmca1DX10, truncates the channel after the IV-S4 transmembrane domain. These mutants die as late embryos because they lack vigorous hatching movements. In the weaker allele, Dmca1DAR66, a cysteine in transmembrane domain I-S1 is changed to tyrosine. Dmca1DAR66 embryos hatch but pharate adults have difficulty eclosing. Those that do eclose have difficulty in fluid-filling of the wings. These studies show that this member of the calcium channel α1 subunit gene family plays a nonredundant, vital role in larvae and adults.