EdU incorporation for FACS and microscopy analysis of DNA replication in budding yeast

Abstract

DNA replication is a key determinant of chromosome segregation and stability in eukaryotes. The yeast Saccharomyces cerevisiae has been extensively used for cell cycle studies, yet simple but key parameters such as the fraction of cells in S phase in a population or the subnuclear localization of DNA synthesis have been diffi cult to gather for this organism. 5-ethynyl-2′-deoxyuridine (EdU) is a thymidine analogue that can be incorporated in vivo and later detected using copper-catalyzed azide alkyne cycloaddition (Click reaction) without prior DNA denaturation. This chapter describes a budding yeast strain and conditions that allow rapid EdU incorporation at moderate extracellular concentrations, followed by its effi cient detection for the analysis of DNA replication in single cells by fl ow cytometry and fl uorescence microscopy.