Cell-Free Synthesis ofRatGrowthHormone

Growthhormonehasbeensynthesized in acell-free systemderived fromKrebsIIascites cells, under thedirection ofRNA preparedfromratpituitary tumor (GC)cells. Growthhormonesynthesized inthecell-free systemwas identified by precipitation withantiserum against growthhormonedeveloped inbaboon,followed by electrophoretic analysis ofthedissolved precipitate on sodiumdodecylsulfate-polyacrylamide gels.RNA from boththemembraneand thepost-membranefractions ofthecytoplasm ofGC cells stimulated protein synthesis inthecell-free system, butonlyRNA fromthemembrane fraction wasfoundtodirect thesynthesis ofgrowthhor- mone. Anunderstanding oftheprocesses involved ingeneexpression ineukaryotic cells will require theability todetect andquanti- tatethemessenger RNAsforparticular proteins. Recently, cell-free systems capable ofinitiating andcompleting the translation ofheterologous orhomologous eukaryotic mes- senger RNAs havebeendeveloped. Messenger RNAsfor embryonic chicken myosin, bovine lensa-crystallin protein, mousehemoglobin, rabbit hemoglobin, duckhemoglobin, mousemyeloma immunoglobin light chain, henoviduct albu- min,andreovirus capid proteins havebeentranslated inare- ticulocyte cell-free system (1-11). Messenger RNAsforrabbit hemoglobin, mouseglobin, humanglobin, mousemyeloma light chain, bovine lens a-crystallin protein, chicken oviduct ovalbumin, HeLacell histones, encephalomyocarditis viral