THE IN VITRO FORMATION OF A DNA-RIBOSOME COMPLEX

Abstract
T2-DNA directing the synthesis of RNA and protein in a DNA-dependent, cell-free reaction has been found to sediment with an abnormally high S value in sucrose density gradients. Anomalous sedimentation of DNA depends upon the synthesis of RNA, the presence of ribosomes, and possibly a third factor(s). These data suggest an intermediate stage in protein synthesis in which DNA is joined to functionally competent ribosomes by means of cRNA. Sedimentation and electron microscopic studies are presented in support of this hypothesis. The implications of this type of intermediate for stabilization of cRNA, polarity of attachment of ribosomes to cRNA, and regulation of enzyme synthesis are discussed.