DOI: 10.5061/dryad.4f4qrfjn0
title: Polarization of yeast cells under different pheromone induction regimens

description: The yeast Saccharomyces cerevisiae undergoes polarized growth in two
 different contexts: budding and pheromone-induced mating. A key difference
 between the two processes is that mating polarization occurs in response
 to an external stimulus, which can be easily manipulated under laboratory
 conditions.  We exploited this property to test the hypothesis
 that the underlying polarity circuit is bistable.  To make this
 test we used microfluidics to precisely control the temporal profile of
 mating pheromone and live-cell imaging to monitor polarization in single
 living cells. Files posted here contain single cell polarity time course
 data under different pheromone regimens. These data clearly demonstrate
 that polarization as a function of pheromone concentration depends on the
 history of the system, a behavior that is a hallmark of bistability. The
 data also re­veal that polarity is rapidly lost following a sudden loss of
 phero­mone.
description: The accompanying "Data_Information" document explains
 how polarization was visualized in living cells, the metric used to
 quantify polarization and a Table summarizing the pheromone regimens under
 which the data were collected.
description: # Polarization of yeast cells under different pheromone induction regimens
 [https://doi.org/10.5061/dryad.4f4qrfjn0](https://doi.org/10.5061/dryad.4f4qrfjn0) Data sets posted here were used to support the experimental observations presented in "Multiscale modeling of bistability in the yeast polarity circuit" (Hladyshau, Guan et al., 2024). A separate file, "Data_Information.docx", briefly describes the data and provides details for the computational methods used to analyze the data. Full details for the experimental methods can be found in (Vered 2018) "Memory and bistability in the pheromone response pathway." Ph.D. Dissertation, University of North Carolina at Chapel Hill. It should be noted that the data in the posted files are from analyses and some trials made independently from those for figures appearing in the Vered thesis dissertation (Vered 2018). ## Description of the data and file structure Data were collected for polarity establishment in yeast responding to mating pheromone (α-factor). Experiments were performed using microfluidic devices to precisely control the temporal profile of mating pheromone and live-cell imaging to monitor the polarity process in single living cells. To visualize polarity assembly and disassembly, we tagged the polarity scaffold protein Bem1 with a yomNeonGreen fluorescent protein. Yeast cells polarize under two contexts. One is in response to pheromone during the G1 phase of the cell cycle, and the other is at bud emergence during the G1 to S transition. To distinguish between the two, we exploited a fluorescently tagged myosin II subunit (Myo1-yomRuby), which localizes to the bud neck during all stages of the cell cycle except G1 ((Bhavsar-Jog and Bi 2017); see Fig 2.4 of (Vered 2018)). We restricted our analysis to pheromone induced-polarization by excluding cells with localized Myo1-yomRuby at the time of pheromone exposure. Cells were dropped from the analysis at the time point where the Myo1 spot appeared and for all subsequent time points. Strain BY4741-198, which expresses both Bem1-yomNeonGreen and Myo1-yomRuby, was used for all polarity experiments. Details of strain construction and all microfluidic procedures are detailed in Lior Vered’s doctoral dissertation (Vered 2018).  Terminal NaN  means the cell has exited G1 and is dropped from the analysis. Any internal NaN means the cell is out of focus in that frame. The data headings indicating different dates of the experiments are colored for visual clarity. No specific color coding was used. The file structure is provided in Table 1 in the "Data_Information.docx" file.  ## Sharing/Access information Relevant references: Bhavsar-Jog, Y. P. and  Bi E. (2017). "Mechanics and regulation of cytokinesis in budding yeast." Semin Cell Dev Biol 66: 107-118. PMCID: PMC5474357 Hladyshau S., Guan K., Nivedita N., Errede B., Tsygankov D., and Elston T.C.  (2024) "Multiscale modeling of bistability in the yeast polarity circuit."  Submitted. Tsygankov D., Chu P. H., Chen H., Elston T.C., and Hahn K. (2014). "User-friendly tools for quantifying the dynamics of cellular morphology and intracellular protein clusters." Methods Cell Biol. 123: 409-427. PMCID: PMC4504218 Vered, L. (2018). "Memory and bistability in the pheromone response pathway." Ph.D. Dissertation, University of North Carolina at Chapel Hill.