Study of Pax3 and Pax7 functions during the development of the mouse embryo Antoine Zalc 2 Université Pierre et Marie Curie & Freie Universität Berlin Ecole doctorale Complexité du Vivant et Myograd Laboratoire UMR-S 974 Study of Pax3 and Pax7 functions during the development of the mouse embryo By Antoine Zalc Directed by Pr. Frédéric Relaix and Pr. Carmen Birchmeier Thesis defence: the 26th of September 2014 In front of an international jury composed of: Claire Fournier-Thibault, Professor, President Simone Spuler, Professor, First Examiner Chaya Kalcheim, Professor, Reviewer Paul Trainor, Professor, Reviewer Sigmar Stricker, Professor, Second Examiner Christian Hiepen, Postdoctoral fellow 3 Table of contents Acknowledgement .......................................................................................................................... 7 List of figures .................................................................................................................................. 12 List of abbreviations .................................................................................................................... 14 INTRODUCTION ............................................................................................................................. 18 Part I Developmental control of limb muscle progenitor cell growth arrest ................ 18 1. Origin of skeletal muscles ......................................................................................................................... 18 1.1. The somite ................................................................................................................................................................ 18 1.2. The somitogenesis ................................................................................................................................................ 23 1.3. Organisation of the mature somite ............................................................................................................... 28 2. Migration to the limb bud and establishment of the muscle masses .................................... 30 3. Muscle differentiation ................................................................................................................................ 33 3.1. The myogenic cascade ........................................................................................................................................ 33 3.2. MRFs binding and control of muscle differentiation ............................................................................. 43 3.3. Muscle growth and regeneration ................................................................................................................... 47 4. Control of cell cycle exit ............................................................................................................................ 52 5. Notch signalling: a crucial regulator of cell fate decision ........................................................... 58 Part II Growth and maintenance of Cranial Neural Crest Cells ........................................... 65 1. Neural crest biology .................................................................................................................................... 65 1.1. Neural crest induction ........................................................................................................................................ 67 1.2. Neural crest cells formation ............................................................................................................................. 71 1.3. Neural crest migration ........................................................................................................................................ 75 2. Development of the craniofacial complex ......................................................................................... 81 2.1. Cranial neural crest cells contribution to the developing face .......................................................... 81 2.2. Gene regulatory networks regulating neural crest cells development and differentiation . 85 2.2.1. Hox genes pattern the neural crest ...................................................................................................... 87 4 2.2.2. Signalling pathways patterning the branchial arches ................................................................. 89 2.2.3. AP-2 genes ...................................................................................................................................................... 93 2.2.4. Dlx genes ......................................................................................................................................................... 93 2.2.5. Sox genes ......................................................................................................................................................... 95 2.2.6. Msx genes ........................................................................................................................................................ 97 2.2.7. Pax genes ......................................................................................................................................................... 99 3. Multipotence of the neural crest cells ............................................................................................... 107 4. Evolution of the neural crest ................................................................................................................. 109 5. Environmental influence on craniofacial development ............................................................ 113 5.1. Environmental risk factors linked to craniofacial defects ................................................................ 113 5.2. Dioxin exposure is linked with craniofacial malformations ............................................................ 115 5.3. AhR signalling pathway mediates dioxin action ................................................................................... 119 RESULTS ........................................................................................................................................ 125 Part I FIRST PAPER .......................................................................................................................... 127 Part II SECOND PAPER – IN REVISION ....................................................................................... 142 DISCUSSION ................................................................................................................................. 184 Abstract ......................................................................................................................................... 223 Résumé .......................................................................................................................................... 225 Abstrakt ........................................................................................................................................ 227 5 6 Acknowledgement This thesis was defended on the 26th of September 2014, in front of an international jury composed of distinguished scientists whom I would like to acknowledge. I thank them for accepting to examine my work. These people are important players in their field of research and will inspire me in my future career. I would like first to thank Pr. Claire Fournier-Thibault, for accepting to be President of my thesis jury. I really like her work and input in the field of developmental biology. I would like to thank my examiner Pr. Sigmar Stricker. I always liked his calm in and his scientific rigor. I would also like to thank Dr. Christian Hiepen for attending my defence. Finally, I would like to thank my reviewers: Pr. Chaya Kalcheim, Pr. Simone Spuler and Pr. Paul Trainor for the time they spent reading my manuscript and writing their reports, as well as attending the defence, which implied travelling across the Rhine, the Mediterranean Sea and the Atlantic Ocean. I heard so much about Pr. Chaya Kalcheim’s work and about her scientific rigor and brightness both on the field of neural crest and muscle biology that she was the obvious person to evaluate my work. Pr. Simone Spuler is the director of the Myograd Ph.D. program; during the time of my Ph.D. she displayed an incredible amount of effort and energy to get Myograd started and to create a scientific emulation for the students. Pr. Paul Trainor is a pillar in the field of neural crest biology. When I met him in Italy in 2011 during the Craniofacial Gordon conference that he was chairing he was always available and invited me to have a drink with his friends several times during the conference. Thank you very much for the discussions, comments and advice about my work. I was lucky to have you all in my thesis jury. 7 In the second part of the acknowledgement I will thank all the people who helped me during these years. First I would like to thank Fred, who decided to recruit me in his lab for my master. Despite my willingness to work on muscles, I’m glad Fred offered me to work on neural crest cells, which I never heard about before. Agronomic studies are great, I learnt many things including how to recognise different races of cows, sheep and goats but the developmental biology was kind of absent from the programs. I would like to thank Fred for his support and his trust during the development of my project and for teaching me