Transcriptional timing and noise of yeast cell cycle regulators—a single cell and single molecule approach

Methods and strategy. a Schematic cell cycle progression of S. cerevisiae. b Principle of smFISH method. A set of fluorescently labeled DNA probes hybridizes with the target mRNA sequence. Single mRNA molecules can be detected by fluorescence microscopy. c SIC1, CLN2, and CLB5 transcription and degradation. S1, S2, and S3 denote signals for transcription upregulation in the models. d Morphological and genetic cell cycle progression markers allow to discriminate seven different cell cycle phases (early G1, late G1, S, G2, P/M, Ana, T/C). Markers used were the presence and size of a bud (first row), the number and orientation of the spindle pole bodies (green spots in second and third rows), the localization of Whi5 (white in second row) and the shape and number of nuclei (blue in third row). Scale bar represents 2？μm. The duration (mean？+/？？SEM) of the phases has been determined according to the number of cells found in each phase (n？>？2600 cells, see Biological Replicates in Supplementary Information