Macromolecule synthesis and breakdown in relation to sporulation and meiosis in yeast

The time course of synthesis and breakdown of various macromolecules has been compared for sporulating (a/alpha) and nonsporulating (a/a and alpha/alpha) yeast cells transferred to potassium acetate sporulation medium. Both types of cells incorporate label into ribonucleic acid and protein. The gel electrophoresis patterns of proteins synthesized in sporulation medium are identical for sporulating and nonsporulating diploids; both are different from electropherograms of vegetative cells. Sporulating and nonsporulating strains differ with respect to deoxyribonucleic acid synthesis; no deoxyribonucleic acid is synthesized in the latter case, whereas the deoxyribonucleic acid complement is doubled in the former. Glycogen breakdown occurs only in sporulating strains. Breakdown of preexisting vegetative ribonucleic acid and protein molecules occurs much more extensively in sporulating than in nonsporulating cells. A timetable of these data is presented.