Molecular Cloning of a Pancreatic Islet-Specific Glucose-6-Phosphatase Catalytic Subunit-Related Protein

摘要

A pancreatic islet-specific glucose-6-phosphatase- related protein (IGRP) was cloned using a subtractive cDNA expression cloning procedure from mouse insuli- noma tissue. Two alternatively spliced variants that dif- fered by the presence or absence of a 188-bp exon (exon I) were detected in normal balb/c mice, diabetic ob/ob mice, and insulinoma tissue. The longer, 1901-bp full-length cDNA encoded a 355-amino acid protein (molecular weight 40,684) structurally related (50/100 overall identity) to the liver glucose-6-phosphatase and exhibited similar predicted transmembrane topology, conservation of catalytically important residues, and the presence of an endoplasmic reticulum retention sig- nal.