Diabetes, Vol 45, Issue 2 262-266, Copyright © 1996 by American Diabetes Association
Mitochondrial glycerol-3-phosphate dehydrogenase. Cloning of an alternatively spliced human islet-cell cDNA, tissue distribution, physical mapping, and identification of a polymorphic genetic marker
J Ferrer, M Aoki, P Behn, A Nestorowicz, A Riggs and MA Permutt
Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
Pancreatic beta-cell mitochondrial glycerol-3-phosphate dehydrogenase
(mGPDH) plays a major role in glucose-induced insulin secretion. Decreased
activity of this enzyme has thus been proposed to play a role in the
pathogenesis of NIDDM. Cloning of human insulinoma mGPDH cDNAs disclosed
the existence of two variant transcripts with different 5' ends. Reverse
transcription polymerase chain reaction (PCR) confirmed the presence of
both mGPDH mRNAs in purified native human pancreatic islets and other
tissues. A major 6.5-Kb mGPDH transcript was detected by Northern blot
analysis in RNA from human and rat pancreatic islets, with distinctly lower
levels in other human tissues, indicating that previously reported high
mGPDH enzymatic activity in beta-cells is determined by high transcript
levels. The mGPDH gene was mapped to chromosome 2 by PCR analysis of
genomic DNA from human/rodent somatic cell hybrids, and five independent
overlapping yeast artificial chromosome (YAC) clones containing the mGPDH
sequence were identified from the Centre d'Etude du Polymorphisme Humain
YAC library. Analysis of these YAC clones identified a highly polymorphic
chromosome 2q21-q33 dinucleotide repeat genetic marker (D2S141) physically
linked to the mGPDH gene. These studies provide the means to investigate
the role of the human mGPDH gene in the pathogenesis of NIDDM and
illustrate the value of a novel strategy to identify genetic markers for
diabetes candidate genes.