Synthesis of ‘Bacterial’ Protein by Cultured Chick Cells

Abstract

PRIMARY isolates of chick embryo fibroblasts cultivated as monolayers were found to resume protein synthesis only after a delay of 24–48 hr. The extent of the lag period was dependent in part on the composition of the medium with which the cells were nourished following release from the embryo by trypsinization. A marked shortening of the lag was observed when phenol-extracted ribonucleic acid (RNA)^1,3 was added to the medium shortly after the cells became attached to the glass (Fig. 1). The effect was abolished by pretreatment of the RNA with ribonuclease and was not duplicated by combinations of nucleosides. RNA preparations obtained from chick embryo, rabbit liver, or Escherichia coli B proved equally effective.