UNIVERSITE SORBONNE PARIS CITE UNIVERSITE PARIS DIDEROT (PARIS 7) THÈSE Pour obtenir le grade de DOCTEUR DE L’UNIVERSITÉ PARIS DIDEROT Spécialité: Biologie synthétique et systémique École Doctorale Frontières du Vivant (ED 474) Laboratoire Matière et Systèmes Complexes (MSC) INRIA Paris Rocquencourt. Effects of repeated osmotic stress on gene expression and growth: from cell-‐to-‐cell variability to cellular individuality in the budding yeast Saccharomyces cerevisiae. Présentée par Artemis Llamosi dirigée par Pascal HERSEN et Gregory BATT Soutenue le 15 décembre 2015 Marc LAVIELLE Directeur de recherche, INRIA Rapporteur Gael YVERT Directeur de recherche, CNRS Rapporteur Peter SWAIN Professeur, University of Edinburgh Examinateur Heinz KOEPPL Professeur, TU Darmstadt Examinateur Gregory BATT Chargé de recherche, INRIA Directeur de thèse Pascal HERSEN Directeur de recherche, CNRS Directeur de thèse Effects of repeated osmotic stress on gene expression and growth Page | 2 M. C. Escher. Reptiles. 1943 Page | 3 Effects of repeated osmotic stress on gene expression and growth Page | 4 Acknowledgments Many people have contributed to the work presented here, through scientific exchange, personal support or both. I had the opportunity to work with many interns during this project: Sebastian Jaramillo Riveri, Matt Deyell, Rémi Sieskind, Alice Llamosi, and Antonio Villarreal Larraui. Thank you all for helping me, whether by lightening my share of ungrateful repetitive tasks or in taking the risk of exploring new research directions. I would like to thank all the members of the MSC lab and the Contraintes/Lifeware team, in particular Jean-‐Marc Di Meglio, François Fages, Benoit Sorre, Gaëlle Charron, Mathieu Receveur, Arnaud Grados et David Pereira. I obviously want to thank all the members of the Lab 513, both past and present. First of all, I would like to thank Jannis Uhlendorf for teaching me so much about working with yeast, doing microfluidics, keeping calm with molecular biology, and tuning microscopes. Also, I am very grateful to Clément Vulin, a friend and a teacher to me. Thanks to you I know why yeast is awesome and I have filled many blanks in my homemade biology education. I would like to thank Jean-‐Baptiste Lugagne, Xavier Duportet, Zoran Marinkovic, Adrien Halou, and Zacchari Ben Meriem for the very good vibes in the lab, the fruitful discussions and the troubleshooting support. I would like to thank my collaborators and in particular Andres Gonzalez-‐Vargas for working with me side by side (although most of the time at distance) with patience and strength. I thank Giancarlo Ferrari-‐Trecate and Eugenio Cinquemani for being our mathematical backbone and for our discussions. I thank Cristian Versari for our collaboration on Cell* and the immense amount of effort you’ve placed in order to create a truly great tool. I thank again Eugenio Cinquemani along with Frédéric Devaux for our yearly advisory committee, which was always useful and benevolent. I would like to thank Véronique Letort, Florence d’Alché-‐Buc and Thomas Landrain who acted as enzymes in catalyzing my transformations from engineering to biology prior to my PhD. I thank my family for their support and Séverine, my life partner who shares the ups and downs of a PhD and is always ready for geek’s chats and late philosophical and scientific debates. Obviously, I will never be able to thank enough my PhD advisors, Pascal Hersen and Gregory Batt. Thank you for believing in me, for your multidimensional support and advice, for your patience, and for your subtle blend of profound expertise and humility. At last, I would like to thank the billions of yeast cell, which, unwillingly, have been the core of this project. Thank you for being so fascinating and for bread,… and beer,… and wine. Page | 5 Effects of repeated osmotic stress on gene expression and growth Page | 6 Table of Contents Acknowledgments ................................................................................................................................... 5 Abstract ................................................................................................................................................. 11 Foreword: Why engineers should study cells? ..................................................................................... 13 General introduction ............................................................................................................................. 15 I. Introduction .................................................................................................................................. 21 1. Dealing with variability and time scale in gene expression ....................................................... 21 a. Twins are not identical .......................................................................................................... 21 b. What a difference a day makes? ........................................................................................... 26 2. Measurements at the single cell level ....................................................................................... 31 3. A synthetic and systems biology approach ............................................................................... 35 a. Cells as systems ..................................................................................................................... 35 b. Experimenting within a cell: Synthetic biology and microfluidics ......................................... 38 4. S. cerevisiae response to osmotic stress ................................................................................... 41 a. An overview of the HOG response ........................................................................................ 41 b. Yeast response to osmotic stress as a model cellular process .............................................. 46 c. Modelling the cellular response to osmotic stress ................................................................ 52 5. Introduction Conclusion and Outline ........................................................................................ 54 II. Long term dynamic experiments and single-‐cell data ................................................................... 55 1. Single-‐cell measurements in precisely changing environments using microfluidics and microscopy ........................................................................................................................................ 56 a. The Truman show: the use of microfluidics .......................................................................... 56 b. Fluorescent probes to peep into cellular activity .................................................................. 61 2. Image Analysis ........................................................................................................................... 64 a. Segmentation and Tracking using Cell* ................................................................................ 64 b. Measures of cellular identity ................................................................................................. 66 3. Measuring growth in populations and single cells .................................................................... 69 a. Going beyond the field of view: An Eulerian measure of population growth ....................... 69 b. Measuring growth at the single cell level .............................................................................. 72 4. Conclusions on: long term dynamic experiments and single cell data ...................................... 74 III. Individuality in the transcriptional response to osmotic stress ................................................ 75 1. Modelling dynamics of gene expression at the single cell level ................................................ 75 a. pSTL1 as a reporter of HOG transcriptional response ........................................................... 75 Page | 7 Effects of repeated osmotic stress on gene expression and growth b. Representing variability in pSTL1 gene expression with stochastic models .......................... 80 c. Identifiability of extrinsic and stochastic models of gene expression at the single-‐cell level84 2. Mixed effects models of pSTL1 expression ............................................................................... 87 a. Building a single-‐cell model of pSTL1 expression including cell-‐to-‐cell variability ................ 87 b. Representing extrinsic variability with using Mixed-‐effects models ..................................... 89 c. Estimating population and single-‐cell models and validating them ...................................... 90 3. Cellular identity and gene expression ....................................................................................... 97 a. Relations between gene expression and cell physiology ...................................................... 97 b. Inheritance of phenotype and gene expression features ..................................................... 98 c. Listening to the noise: harvesting natural cell to cell variability ......................................... 101 4. Conclusions on: Individuality in the transcriptional response to osmotic stress .................... 103 IV. The impact of repeated stress on cellular proliferation .......................................................... 109 1. An integrated view of the response to osmotic stress ............................................................ 111 a. How osmotic stress affects growth and division? ............................................................... 111 b. Proliferation quantification at the single cell level: a matter of point of view .................... 113 2. The impact of osmotic stress on the cell cycle ........................................................................ 116 a. Osmotic stress can trigger phase-‐dependent arrest of the cell cycle ................................. 116 b. Nuclear separation is perturbed by osmotic stress ............................................................. 119 c. Timing of cell cycle arrest and partial lock-‐in ...................................................................... 123 d. Lock-‐in phenomenon .......................................................................................................... 127 3. The impact of osmotic stress on metabolism ......................................................................... 131 a. Metabolism shifts upon osmotic stress ............................................................................... 131 b. Quantifying adaptation variable cost .................................................................................. 132 c. Quantifying acclimation costs of osmotic fluctuation ......................................................... 136 4. Conclusion: The impact of osmotic stress on colony growth dynamics .................................. 140 V. Perspectives and final discussion ................................................................................................ 143 1. Experimental pipelines for systems biology at the single-‐cell level ........................................ 143 2. Cellular variability and context ................................................................................................ 147 List of abbreviations ............................................................................................................................ 153 References .......................................................................................................................................... 154 Appendix ............................................................................................................................................. 167 1. List of Strains ........................................................................................................................... 168 2. The use of S. cerevisiae ........................................................................................................... 169 3. Transcriptome time course in response to hyperosmotic stress ............................................ 172 Page | 8 4. Custom microfluidic chips fabrication method ....................................................................... 173 5. Glucose diffusion and consumption in microfluidic chambers ............................................... 176 6. Single-‐cell parameter estimation of models of gene expression (article, submitted version) 185 7. Simulation of Eigen cell behavior ............................................................................................ 230 8. Developing an Open Source, single-‐cell optogenetic system .................................................. 231 Page | 9 Effects of repeated osmotic stress on gene expression and growth Page | 10
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