Chapter VII 



Kinetic Studies of the Synthesis 

 of RNA and Ril^osonies 



R. B. ROBERTS, R. J. BRITTEN, and 



B. J. McCarthy 



Carnegie Institution of Washington, 

 Department of Terrestrial Magnetism, 

 Washington, D. C. 



I. Introduction 292 



A. Microsomes and Ribosomes 292 



B. Effects of Magnesium 293 



C. Other Influences on Ribosome Patterns 296 



D. Generality of Ribosome Patterns 298 



E. Ribosomes as Site of Protein Synthesis 299 



II. Properties of Ribosomes in Vitro 299 



A. Preparation and Purification of Ribosomes 299 



B. Protein/Nucleic Acid Ratio 300 



C. Protein Components 302 



D. Nucleic Acid Components 305 



E. Structure of Ribosomes 306 



III. Fractionation of Ribosomes 308 



A. Chromatography 308 



B. Sedimentation Analysis 309 



C. Density Gradient Banding 310 



D. Electrophoresis 310 



E. Two-Phase Systems 310 



F. Conclusion 310 



IV. Metabolic Pools 311 



V. Kinetics of Incorporation into RNA of Ribosomes ..... 315 



A. DEAE Chromatography 315 



B. Sedimentation Analysis 316 



C. Quantitative Kinetic Analy.sis 321 



D. Stages of Synthesis of the Ribosomal RNA ...... 326 



VI. Kinetic Studies of Phenol-Extracted RNA ....... 329 



VII. Kinetics of Incorporation into Protein ....•••■ 331 



A. Incorporation of C"-Leucine into the Ribosomes ..... 331 



B. Effect of Chloramphenicol on Ribosome Synthesis .... 333 



C. Assembly of the Ribosomes 333 



VIII. Composition of Newly Formed RNA 335 



A. Ambiguities 335 



B. Time Course of Composition 337 



C. Fractionation 338 



291 



