Ablation of stimulation of a cAMP-responsive promoter in CHO cell lines defective in their cAMP-dependent protein kinase system

Publisher Website
Google Scholar
Abstract
We have studied the requirement for an intact cAMP-dependent protein kinase (PKA) system to regulate cAMP-mediated gene transcription in Chinese hamster ovary (CHO) cells. Wild-type CHO cells and mutant CHO cell lines selected for their resistance to the growth inhibitory effect of 8-Br-cAMP and defective in their PKA system were transiently transfected with reporter plasmids containing 2.5 and 3.0 kb of the 5′-flanking sequence of the rat tyrosine aminotransferase (TAT) gene promoter. This segment of DNA contains no CRE-like sequences, yet wild-type transfectants exhibited a specific increase in TAT promoter activity following growth in medium containing 8-Br-cAMP. In CHO cell lines defective in their PKA, the transfected TAT promoter failed to respond to cAMP treatment. We conclude that an intact PKA system is necessary for the cAMP-mediated increase in TAT promoter activity in CHO cells and that there is no requirement for a CRE to see this effect.