Messenger RNA for glutamine synthetase: its partial purification, translation in a cell-free system and its regulation by hydrocortisone

Abstract

Messenger RNA for glutamine synthetase (GS), extracted from polysomes of embryonic chick retina cells, was partially purified by chromatography on oligo (dT)-cellulose on the basis of its poly (A)-content and translated in a cell-free protein synthesizing system derived from wheat germ. Identification and quantitation of GS in the products of cell-free synthesis was achieved by immunoprecipitation of the enzyme and electrophoresis in sodium-dodecyl-sulfate polyacrylamide gels. Comparison of the amount of GS synthesized in vitro by equal amounts of mRNA purified from polysomes of control or hydrocortisone induced retina indicate that the hormone elevates the level of GS mRNA on the polysomes from induced cells.