CDNA SEQUENCE AND EXPRESSION OF A GENE ENCODING A PYRUVATE-DEHYDROGENASE KINASE HOMOLOG OF DROSOPHILA-MELANOGASTER

Pyruvate dehydrogenase is a catalyst for an irreversible step in the d egradation of glucose and its activity is regulated by a highly specif ic protein kinase, pyruvate dehydrogenase kinase (PDK). PDK belongs to a family of mitochondrial protein kinases unique from other eukaryoti c protein kinases. We cloned a cDNA encoding a putative PDK from Droso phila melanogaster (DmPDK). The deduced DmPDK consists of 413 amino ac ids and shares up to 57.8% homology with human and rat PDK isoenzymes. Developmental Northern blot analysis revealed two major transcripts o f 2.1 kb and 2.7 kb. The 2.7-kb transcript was expressed throughout on togeny, whereas the 2.1-kb transcript was specific to embryos and adul t females. Whole-mount in situ hybridization revealed that PDK mRNA is ubiquitously distributed in the embryo. The DmPdk gene was cytologica lly mapped to the 45CD region on the right arm of the second chromosom e.