MOLECULAR CHARACTERIZATION OF THE DROSOPHILA MO25 GENE, WHICH IS CONSERVED AMONG DROSOPHILA, MOUSE, AND YEAST

To study the general physiological role of the Mo25 gene, which has be en cloned from mouse cleavage-stage embryos, we isolated a Drosophila equivalent, dMo25, cDNA from an embryo cDNA library, The 2,222 nucleot ides contained a single open reading frame encoding a polypeptide of 3 39 amino acid residues with a calculated molecular mass of 39,278 dalt ons, The deduced amino acid sequence of the dMo25 cDNA had 69.3% ident ity with mouse Mo25, A homology search revealed that these were simila r to a protein encoded in an open reading frame near the calcineurin B subunit gene on chromosome XI in Saccharomyces cerevisiae. In particu lar, the carboxy-terminal region was highly conserved in Drosophila, m ouse, and yeast. The dMo25 gene was mapped to the left arm of the thir d chromosome at 73AB, and 2.3- and 1,8-kb mRNA bands were detected dur ing development and in adult Drosophila. Conservation of the gene stru cture and the wide expression profile indicated that the function of t he gene is likely to be fundamental in many cell types as well as duri ng development.