Regulation of insulin gene expression by glucose and calcium in transfected primary islet cultures |
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Authors: | M S German L G Moss W J Rutter |
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Institution: | Hormone Research Institute, University of California, San Francisco 94143-0534. |
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Abstract: | To study the regulation of insulin gene expression by physiological regulators, primary cultures of rat islet cells were transfected with portions of the rat insulin I gene 5'-flanking sequence linked to the reporter gene chloramphenicol acetyltransferase (CAT). Incubation of the cells in increasing glucose concentrations led to a parallel increase in both CAT activity and CAT mRNA levels. Pretreatment of the cells with the beta-cell-specific toxin streptozotocin reduced CAT activity 97%. Beta-Cell-specific expression of CAT was also demonstrated by co-staining the transfected cells with antisera to both CAT and insulin. Experiments showing a reduction in the response to glucose in the presence of the calcium channel blocker verapamil suggest that calcium plays a role in the glucose response, possibly via regulation of factors interacting with this limited portion of the insulin gene. |
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