Genetic Expression in the Cell Cycle provides an understanding of the molecular mechanisms that govern the expression of genetic information during the cell cycle. The initial five chapters describe the intimate relationships between the supramolecular complexes that form the basic structure of chromatin. Emphasis is placed on the dynamics of cycle-dependent changes in the structural organization of some of these components. Subsequent chapters demonstrate that small nuclear RNAs (Sn RNA) are actively involved in gene regulation in eukaryotic cells; discuss the relationship between cell cycle regulation in the yeast Saccharomyces cerevisiae and transcription of ribosomal RNA genes; and describe the use of conditional lethal mutants to study the regulation of the cell cycle of eukaryotic cells. The remaining chapters discuss the concepts and methodologies employed to isolate and study specific cell cycle mutants of S. cerevisiae; the antiproliferative effect of interferon on cultured human fibroblasts; and the role of cell membrane and related subcellular elements in the control of proliferation, differentiation, and cell cycle kinetics.