Quantitative analysis of glucose-6-phosphate translocase gene expression in various human tissues and haematopoietic progenitor cells

We investigated the quantitative expression of the human glucose-6-phosphat e translocase gene (G6PT1) and its splicing variants in human tissues. The G6PT1 gene was strongly expressed in liver, kidney and haematopoietic proge nitor cells, which might explain major clinical symptoms such as hepatomega ly, nephromegaly and neutropenia in glycogen storage diseases type Ib. Reve rse transcriptase-mediated PCR amplification of G6PT1 cDNA revealed several splicing variants in tissue-specific manners. The brain-specific isoform, which has an additional 22 amino acids between exons 6 and 8, was also iden tified in heart and skeletal muscle. A new splicing variant, although less prominent in quantity and lacking polypeptide loops corresponding to exons 2 and 3, may have a distinct substrate affinity or specificity in leukocyte s and haematopoietic progenitors. In conclusion, the G6PT1 gene was express ed in various tissues, and alternative splicing variants exist in tissue-sp ecific manners.