ISOLATION, MAPPING, AND FUNCTIONAL EXPRESSION OF THE MOUSE X-CHROMOSOME GLYCEROL KINASE GENE

Glycerol kinase (Gyk) participates in the metabolism of endogenously d erived and dietary glycerol. Deficiency of the human enzyme activity i s an X-linked recessive disorder with a clinical picture varying from childhood metabolic crisis to asymptomatic adults incidentally identif ied by hyperlipidemia screening (pseudohypertriglyceridemia). Gyk is a member of a small group of kinases termed ambiquitous enzymes that ar e found in the cytosol or as membrane-bound enzymes associated with th e voltage-dependent anion channel of the mitochondrial outer membrane. It was recently reported that in humans there are X-linked and autoso mal copies of Gyk sequences, both apparently functional genes and proc essed pseudogenes. To understand the role of Gyk in normal metabolism and the variable clinical features seen with Gyk deficiency, we have c haracterized the mouse Gyk gene. We present the sequence of a full-len gth mouse Gyk cDNA that is alternatively spliced in brain. The Gyk gen e was mapped to the mouse X chromosome by both fluorescence in situ hy bridization and an interspecies backcross panel, demonstrating conserv ation of synteny with dmd. To confirm the functional identity of the c DNA, transient transfection of the cDNA into COS7 cells was shown to c ause a marked elevation in glycerol kinase activity. (C) 1996 Academic Press, Inc.