DEVELOPMENTAL AND TISSUE-SPECIFIC SULFONYLUREA RECEPTOR GENE-EXPRESSION

We have studied the developmental regulation of mouse sulfonylurea rec eptor (SUR) gene expression throughout several embryonic stages as wel l as in the adult mouse. To this end we used a 229-bp mouse complement ary DNA corresponding to the 3'-end of the SUR gene for in situ hybrid ization and solution hybridization/ribonuclease protection assays. We found that the SUR gene was expressed as early as embryonic day 12 in the developing pancreas, heart, and central nervous system. These tiss ues maintained significant levels of SUR messenger RNA (mRNA) througho ut development. In addition, SUR mRNA was detected in the submandibula r gland, anterior duodenum, dorsal root ganglia, lens, retina, and vib rissae by late developmental stages. SUR mRNA is widely distributed in adult mouse tissues, with the exception of the liver. In the adult pa ncreas, the SUR gene was expressed exclusively in endocrine tissue. Al though significant levels of SUR mRNA were broadly seen throughout the brain, neurons of the cerebellum, hippocampus, and thalamus had espec ially high levels of SUR mRNA. These findings support the idea that th e SUR has important functions in many other tissues in addition to the islets of the pancreas.