Calx , a Na-Ca exchanger gene of Drosophila melanogaster

Calx, a Na-Ca exchanger gene of Drosophila melanogaster

Erich M. Schwarz* and
Seymour Benzer†

Division of Biology, 156–29, California Institute of Technology, Pasadena, CA 91125

Contributed by Seymour Benzer

Abstract

We have cloned Calx, a gene that encodes a Na-Ca exchanger of Drosophila melanogaster. Calx encodes two repeated motifs, Calx-α and Calx-β, that overlap domains required for exchanger activity and regulation. Calx has multiple transcripts in adults, including at least one expressed in the retina. The Calx genomic locus comprises ≥35 kb between the Atpα and rudimentary-like genes in chromosomal region 93B. In Xenopus oocytes, microinjected Calx cRNA induces calcium uptake like that of its homolog, the 3Na⁺-1Ca²⁺ exchanger of mammalian heart. Implications of Calx-α motifs for the mechanism of Na-Ca exchange are discussed.

Footnotes

↵ * Present address: Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027.
↵ † To whom reprint requests should be addressed. e-mail: benzers{at}starbase1.caltech.edu.
Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. AF009897).
ABBREVIATIONS:

Cai2+,

cytoplasmic calcium;

NCX1,

-2, and -3, paralogous mammalian 3Na+-1Ca2+ exchangers;

NCKX1,

4Na+-1Ca2+,1K+ mammalian retina exchanger