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 degradation of glucose and its activity is regulated by a highly specific protein kinase, pyruvate dehydrogenase kinase (PDK). PDK belongs to a family of mitochondrial protein kinases unique from other eukaryotic protein kinases. We cloned a cDNA encoding a putative PDK from Drosophila melanogaster (DmPDK). The deduced DmPDK consists of 413 amino acids and shares up to 57.8% homology with human and rat PDK isoenzymes. Developmental Northern blot analysis revealed two major transcripts of 2.1 kb and 2.7 kb. The 2.7-kb transcript was expressed throughout ontogeny, whereas the 2.1-kb transcript was specific to embryos and adult females. Whole-mount in situ hybridization revealed that PDK mRNA is ubiquitously distributed in the embryo. The DmPdk gene was cytologically mapped to the 45CD region on the right arm of the second chromosome.