PANCREAS SPECIFIC GENES AND THEIR EXPRESSION DURING DIFFERENTIATION

Pancreas-specific messenger RNAs, in particular that for amylase, have been measured during the course of development. In addition the modulation of specific gene expression during differentiation in vitro by bromodeoxyuridine and the glucocorticoid, dexamethasone, has been examined. BrdU depresses the accumulation of all of the tissue-specific mRNAs. Dexamethasone selectively increases the concentration of amylase mRNA. Changes in the levels of mRNAs correlate directly with changes in the levels of pancreas-specific proteins. Pancreatic rudiments release into the incubation medium a characteristic subset of cellular proteins. Some of these, including amylase, represent the secretory digestive (pro)enzymes. Another group of proteins are also released by immature rudiments which have not yet accumulated the digestive enzymes. Some of these proteins persist throughout development and may be diagnostic of and functionally associated with pancreatic differentiation.