Journal of Neuroscience, Vol 13, 2186-2198, Copyright © 1993 by Society for Neuroscience
An invertebrate calcium-binding protein of the calbindin subfamily: protein structure, genomic organization, and expression pattern of the calbindin-32 gene of Drosophila
R Reifegerste, S Grimm, S Albert, N Lipski, G Heimbeck, A Hofbauer, GO Pflugfelder, D Quack, C Reichmuth and B Schug
Theodor Boveri Institut fur Biowissenschaften, Lehrstuhl fur Genetik, Wurzburg, Germany.
Antisera against vertebrate calcium-binding proteins cross-react with
Drosophila nervous and muscle tissue. We have used an antiserum against
carp parvalbumin to isolate from a Drosophila head cDNA library
immunopositive expression clones. Tissue in situ hybridization identified a
clone that labeled specific neurons and muscles similar to the
parvalbumin-like immunohistochemical staining pattern. Five independent
cDNAs derive from an mRNA whose open reading frame codes for a 310 amino
acid polypeptide. Sequence analysis identifies six EF- hand calcium-binding
domains and reveals 42% and 37% homology to chicken calretinin and
calbindin D-28k, respectively. Since the positions of 9 out of 10 introns
within the ORF are conserved from the Drosophila gene to both vertebrate
genes, we conclude that we have identified the first invertebrate member of
the calbindin sub-family of calcium-binding protein genes of the EF-hand
homolog family. The calbindin-32 gene (cbn) maps to 53E on the second
chromosome. It is expressed through most of ontogenesis with a selective
distribution in the nervous system and in a few small adult thoracic
muscles. The cloning of a Drosophila homolog to vertebrate neuronal
Ca(2+)-binding proteins opens new routes to study the so far largely
elusive function of these brain molecules.