Cell-Cycle Analysis of Fission Yeast Cells by Flow Cytometry

The cell cycle of the fission yeast, Schizosaccharomyces pombe, does not easily lend itself to analysis by flow cytometry, mainly because cells in G1 and G2 phase contain the same amount of DNA. This occurs because fission yeast cells under standard growth conditions do not complete cytokinesis until after G1 phase. We have devised a flow cytometric method exploiting the fact that cells in G1 phase contain two nuclei, whereas cells in G2 are mononuclear. Measurements of the width as well as the total area of the DNA-associated fluorescence signal allows the discrimination between cells in G1 and in G2 phase and the cell-cycle progression of fission yeast can be followed in detail by flow cytometry. Furthermore, we show how this method can be used to monitor the timing of cell entry into anaphase. Fission yeast cells tend to form multimers, which represents another problem of flow cytometry-based cell-cycle analysis. Here we present a method employing light-scatter measurements to enable the exclusion of cell doublets, thereby further improving the analysis of fission yeast cells by flow cytometry. © 2011 Knutsen et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited