Cyclic AMP stimulates the gene expression of a non-selective cation channel, mNSC1, in pancreatic beta-cell line, MIN6

Mouse non-selective cation channel 1 (mNSC 1) cDNA from mouse pancreatic be ta-cell line, MIN6, have recently been cloned. Since the number of non-sele ctive cation channel in pancreatic duct cells has been reported to increase 9-fold in 5 h incubation with cAMP, the effect of cAMP on the gene express ion of mNSC1 in MIN6 cells was examined. Dibutyryl cAMP (db-cAMP) was shown to increase the level of the mRNA by reverse transcription-polymerase chai n reaction (RT-PCR). The copy number of the mRNA was increased 4-fold in 6 h incubation with db-cAMP by competitive PCR. Western blot analysis also in dicated a 4-fold increase in the quantity of the newly synthesized protein in 9 h incubation with db-cAMP. Experiments with 5'-flanking region and wit h a transcriptional inhibitor suggested that db-cAMP affected transcription , and protected the mRNA from its degradation as well. It is concluded that the expression of mNSC1 is indeed increased by cAMP in the pancreatic beta -cells. (C) 2000 Published by Elsevier Science Ireland Ltd. All rights rese rved.