STRUCTURAL CHARACTERIZATION AND TISSUE-SPECIFIC EXPRESSION OF THE MOUSE GLUCOSE-6-PHOSPHATE-DEHYDROGENASE GENE

Glucose-6-phosphate dehydrogenase (G6PD) activity differs among tissue s and, in liver, with the dietary state of the mouse, Tissue-specific differences in G6PD activity in adipose tissue, liver, kidney, and hea rt were associated with similar differences in the amount of G6PD mRNA , Regulation of mRNA amount by dietary fat was only observed in liver, In mice fed a low-fat diet, the relative amounts of G6PD mRNA were 3: 1:1:0.38, respectively, in the four tissues, Further, the amount of pr ecursor mRNA for G6PD in liver, kidney, and heart reflected the amount of mature mRNA in these tissues, suggesting differing transcriptional activity, Our S1 nuclease and primer-extension analyses indicated tha t the same transcriptional start site is used in liver, kidney, and ad ipose tissue, resulting in a common 5' end of the mRNA in these tissue s, Thus, differential regulation is not attributable to alternate prom oter usage, A DNase hypersensitivity analysis of the 5' end of the G6P D gene identified three hypersensitive sites (HS): HS 1 and HS 2 were present in all tissues, whereas HS 3 was liver specific, Thus, regulat ion of G6PD expression involves both dietary and tissue-specific signa ls that appear to act via different mechanisms.