Advances in Cell Biology has been initiated as a continuing, multi-volume series to report on the progress of a wide spectrum of problems of cell structure and cell function. Jn arranging these volumes individual contributors are asked not only to review the major new information, but especially to present the state of a given problem or area by discussing the current central issues, speculations, concepts, hypotheses, and technical problems. We intend, in addition, that these volumes will not be concerned with comprehensive reviews of the recent literature but will consist rather of presentations of an interpretive and integrative nature, based on selection of major research advances. It is our aim that these volumes should provide the means whereby cell biologists may keep themselves reasonably well informed about the current progress in research areas in cell biology in which they are not immediately or directly involved themselves. The articles, nevertheless, are expected to bring into focus the experimental objectives of the specialists in a given research area. D. M.P. L. G. E.M. vii Contents Contributors v Preface vii 1 1. The Regulation of DNA Synthesis in Eukaryotes James Douglas Watson 2. D*RNA Containing Ribonucleoprotein Particles and Messenger RNA Transport 47 G. P. Georgiev and 0. P. Samarina Recent Developments in the Synchronization of 3. Tetrahymena Cell Cycle 111 Eric Zeuthen 153 4. Repetitious DNA Christopher Bostock 5. Mitosis 225 R. Bruce Nicklas Specific Enzyme Production in Eukaryotic Cells 299 6.