Lionel Christiaen

Position

Head of Department, Director of the Michael Sars Centre

Affiliation

Short info

I am a developmental systems biologist who seeks to understand how gene regulation and cell-cell signaling coordinate fate choices and cellular behaviors during animal development, regeneration and evolution; and how these processes respond and adapt to diverse environmental conditions.
Research

Since 2009, my lab has been mainly focused on cardiopharyngeal lineages, which produce both cardiomyocytes of the second heart field and head muscles from Mesp1+ anterior mesoderm progenitors. The cardiopharyngeal paradigm casts new light on certain congenital diseases characterized by the co-occurence of cardiac and craniofacial defects, such as the DiGeorge/22q11.2 deletion syndrome. The latter is thought to emerge from haploinsufficiency of TBX1, a key determinant of cardiopharyngeal progenitors. This illustrates the biomedical relevance of our work on the regulation of cardiopharyngeal multipotency and early heart vs. pharyngeal muscle fate choices. 

Circumventing the complexity of vertebrates, we use embryos, larvae and juveniles of the tunicate Ciona to study cardiopharyngeal development with high spatial and temporal resolution. In ascidians like Ciona, every invariant division and migratory event is mapped onto a stereotyped and evolutionarily conserved embryonic sequence. We strive to develop state-of-the-art methods to study Ciona development, including targeted genome engineering with CRISPR/Cas9, single cell genomics, quantitative imaging and mathematical modeling.  Leveraging the simplicity of the Ciona model and our extensive experimental toolkit, we pursue a system’s level understanding of cellular behaviors with a focus on collective polarity, directed migration, and oriented and asymmetric cell divisions. Since joining the Michael Sars Centre, and in collaboration with Dr. Fabienne Lescroart, we have been expanding our work on cardiopharyngeal development toward mammalian stem cell models, by adopting an emerging gastruloid paradigm.

Remarkably, Ciona embryos follow a stereotyped developmental sequence across a wide range of temperatures and environmental conditions across latitudes. This indicates that even deterministic embryogenesis has built-in regulative mechanisms at the cellular and molecular levels, to canalize embryogenesis toward the production of a swimming larva. To study how this is achieved, and why embryogenesis fails beyond the permissive range of environmental conditions, we are expanding the scope of our research towards environmentally-relevant problems in developmental systems biology.

Finally, Tunicates also offer a unique system to study the genomic control of both deterministic and regulative modes of development. Indeed, while embryos cannot compensate for the loss of defined lineages, juveniles and adults can regenerate a variety of tissues and organs, including the central nervous system and the heart, thus displaying a high degree of regulative ability, albeit using the same genome that strictly canalizes embryogenesis. By expanding our work toward post-embryonic stages of development, we seek to uncover the fundamental bases of deterministic vs. regulative modes of cell fate decisions and cellular behaviors during development and regeneration in changing oceans.

Outreach

As an active scientist, my work is disseminated primarily through publications and presentations at conferences and seminar series. The latter include:

Invited Seminars at Universities/Institutes

  1. 2024  CENTURY DAY, Institut de Biologie du Développement de la Méditerrannée (IBDM), CNRS, Marseille, France (invited speaker)
  2. 2024  La Timone Hospital, Marseille, France (invited speaker)
  3. 2024  Université Libre de Bruxelles, seminar series (invited speaker)
  4. 2024  Embryology course, Marine Biological Laboratory, Woods Hole, USA (Invited lecturer)
  5. 2023  Strasbourg, Students seminar (invited speaker)
  6. 2022  Observatoire Océanographique de Villefranche-sur-Mer, France (invited speaker)
  7. 2022  La Timone Hospital, Marseille, France (invited speaker)
  8. 2022  José Luis Gomez Skarmeta Zoominar Series (invited speaker)
  9. 2021  CRBM, CNRS, Montpellier, France (invited seminar speaker)
  10. 2021  Observatoire Océanologique de Banyuls, France (invited seminar speaker)
  11. 2021  BBB seminar series, Faculty of Biomedicine, University of Bergen, Norway (invited seminar speaker)
  12. 2020  University of Colorado, Denver (invited seminar speaker) - postponed
  13. 2020  California Institute of Technology (invited seminar speaker)
  14. 2019  Stazione Zoologica Anton Dhorn, Naples (Italy) (invited seminar speaker)
  15. 2019  Sars International Center for Molecular Marine Biology, Bergen (Norway) (Invited seminar speaker)
  16. 2019  Hospital for Sick Children, Toronto, Developmental and Stem Cell Biology talks (invited speaker)
  17. 2019  Johns Hopkins University, Cell Biology department, Seminar series (invited speaker)
  18. 2019  Icahn School of Medicine, Mount Sinai, Seminar Series (invited speaker)
  19. 2019  Michigan State University, Seminar series (invited speaker)
  20. 2018  Stowers Institute, Kansas City, Seminar series (invited speaker)
  21. 2018  Max Delbrück Center for Molecular Medicine (MDC), Berlin Institute for Medical Systems Biology (BIMSB), Berlin (invited seminar speaker)
  22. 2018  Université Nice Sofia Antipolis, Valrose Institute of Biology (invited speaker)
  23. 2018  University of Zürich (Switzerland), Institute of Molecular Life Sciences (invited speaker)
  24. 2018  University of Geneva (Switzerland), Department of Genetics & Evolution (invited speaker)
  25. 2018  University of California Santa Barbara, Department of Molecular Cellular and Developmental Biology (invited speaker)
  26. 2017  MBL course - Gene Regulatory Networks in Development, Woods Hole, MA (invited instructor)
  27. 2017  CUNY, Stony Brook, NY (invited speaker)
  28. 2017  Center for Integrative Biology, Toulouse (France), Seminar Series (invited speaker)
  29. 2017  NYU Center for Systems Genomics, NYU Langone Medical Center (invited speaker)
  30. 2017  Skirball Institute for Biomolecular Medicine, NYU Langone Medical Center, Seminar series (invited speaker)
  31. 2016  Biocenter, Vienna, Seminar series (invited speaker)
  32. 2015  Queens College, Seminar Series (invited speaker)
  33. 2015  St John's University, Queens Campus (New York, NY), Seminar Series (invited speaker)
  34. 2014  Karolinska Institute, Stockholm, Sweden (invited speaker)
  35. 2012  Columbia University Medical Center, Department of Genetics and Developmental, Seminar Series (invited speaker)
  36. 2011   University of California Santa Barbara, Department of Molecular Cellular and Developmental Biology, (invited speaker)
  37. 2011   Duke University, Biology Department (invited speaker)
  38. 2010  Oceanographic Observatory, Villefranche-sur-Mer, France (invited speaker)
  39. 2009  Curie Institute, Paris, France (job talk)
  40. 2009  Pasteur Institute, Paris, France (job talk)
  41. 2009  NYU Biology, New York, NY (job talk)
  42. 2008  Institute for Functional Genomics, Montpellier, France (job talk)
  43. 2008  European Molecular Biology Laboratory, Heidelberg, Germany (job talk)
  44. 2008  Institute for Developmental Biology of the Mediterranean, Marseille, France (job talk)
  45. 2006  Institute of Neurobiology Alfred Fessard, CNRS, Gif-sur-Yvette, France (invited speaker)
  46. 2005  Oceanographic Observatory, Villefranche-sur-Mer, France (invited speaker)
  47. 2005  European Molecular Biology Laboratory, Heidelberg, Germany (invited speaker)

 

Invited or Selected Speaker at Meetings

  1. 2024    From Cell to Organism, French Society for Developmental Biology, Sorbonne University, Paris, France (invited speaker)
  2. 2024    Nordic EMBL partnership meeting, Oslo, Norway (invited speaker)
  3. 2024    12th International Tunicate Meeting, UC Santa Cruz, CA, USA (selected speaker)
  4. 2024    “Cellular and Molecular Mechanisms of Development and Regeneration”, Shiv Nadar Institution of Eminence (SNIoE), Delhi-NCR, New Delhi (India) (invited speaker)
  5. 2023    22q11 Deletion Syndrome conference, Stanford (CA, USA) (keynote speaker)
  6. 2023    International Society of Regenerative Biology, Vienna (Austria) (invited speaker)
  7. 2023    Conference Jacques Monod, Roscoff (France) (invited speaker)
  8. 2023    EMBRC-FR General Assembly, Banyuls (France) (invited speaker)
  9. 2022    EMBL partnership conference, Heidelberg (Germany) (invited speaker)
  10. 2022    3rd Nordic Meeting on Development, Stem Cells and Regeneration, Copenhagen (Denmark) (invited speaker)
  11. 2022    11th International Tunicate Meeting, Kobe (Japan) (selected speaker)
  12. 2022    EuroEvoDevo meeting, Naples (Italy) (invited speaker).
  13. 2020    Hindsight 2020 meeting, Allen Institute on cell lineage and developmental recording, Seattle (invited speaker). Cancelled
  14. 2020    NYU Abu Dhabi, Genomics Symposium, Abu Dhabi, UAE (invited speaker).
  15. 2020    Emerging Model Systems workshop, McGill's Bellairs Research Station, Barbados (invited speaker)
  16. 2018    9th Aquatic Models of Human Disease Conference, MBL, Woods Hole, MA (invited speaker)
  17. 2017    7th NHLBI Symposium on Cardiovascular Regenerative Medicine, NIH, Bethesda (invited speaker).
  18. 2017    Gordon Research Conference - Developmental Biology (invited speaker)
  19. 2017    Sea urchin meeting, MBL, Woods Hole, MA (invited speaker, declined)
  20. 2017    North East Society for Developmental Biology Meeting, Marine Biological Laboratory, Woods Hole, MA (invited speaker)
  21. 2017    Keystone Symposium "heart development" (invited speaker)
  22. 2016    "GRNs in Development" workshop, Caltech (invited participant)
  23. 2015    8th International Tunicate Meeting, Japan (scientific committee member)
  24. 2015    Society for Developmental Biology, Snowbird Resort, Utah (invited speaker)
  25. 2015    Max Delbrück Center, Berlin Institute for Molecular Systems Biology, Berlin, Germany (invited speaker)
  26. 2015    Weinstein conference in cardiovascular development, Boston, MA (selected speaker)
  27. 2015    American Association of Anatomists Annual Meeting, Boston, MA (invited speaker)
  28. 2014    Developmental Biology meeting, UC Santa Cruz (selected speaker)
  29. 2014    First Heart-Head Muscle Evo-Devo meeting, Howard University, Washington, DC (invited speaker)
  30. 2014    American Association of anatomists, Annual Meeting, San Diego, CA (Young Investigator Award Lecture)
  31. 2014    North East Society for Developmental Biology Meeting, Marine Biological Laboratory, Woods Hole, MA (invited speaker)
  32. 2013    7th International Tunicate Meeting, Naples, Italy (invited speaker)
  33. 2013    Gordon Research Conference - Myogenesis, Lucca, Italy (selected speaker)
  34. 2012    Sea Urchin Meeting, Woods Hole, MA (invited speaker)
  35. 2012    European Evo-Devo Meeting, Lisbon, Portugal (invited speaker).
  36. 2011    Developmental Dynamics workshop, Kavli Institute for Theoretical Physics, UC Santa Barbara, CA (invited speaker).
  37. 2011    6th International Tunicate Meeting, Montréal, Canada (selected speaker)
  38. 2010    Evo-Devo Workshop, Howard Hughes Medical Institute, Chevy Chase, MD (invited speaker)
  39. 2010    Gene Regulatory Network Course, Marine Biological Laboratory, Woods Hole, MA (invited instructor)
  40. 2010    North East Society for Developmental Biology Meeting, Marine Biological Laboratory, Woods Hole, MA (invited speaker)
  41. 2009    5th International Tunicate Meeting, Okinawa, Japan (selected speaker)
  42. 2007    Evo-devo workshop, UC Berkeley Center for Integrative Genomics, Moorea, Tahiti (invited speaker)
  43. 2007    4th International Tunicate Meeting, St Jean Cap Ferrat, France (selected speaker)
  44. 2005    3th International Tunicate Meeting, Santa Barbara, CA, USA (selected speaker)

 

Most of my work on communication and outreach, which I consider an integral part of the scientific process, goes through our initiatives at the Michael Sars Centre

Teaching

I have a long experience  teaching at New York University for 11 years: molecular and cell biology to Sophomores (2nd year), Developmental Biology to juniors and seniors (3rd and 4th year), as well as related topics to graduate students, MS and PhD, including both lectures, paper discussions and thesis supervision.

My training comprised passing the french "Agrégation de Sciences de la Vie et de la Terre" in 1997, which is a competitive teaching degree for high-school professors of Life and Earth Sciences.

Publications
Academic article

See a complete overview of publications in Cristin.

Google Scholar

Pubmed

Publications pending peer review (Preprints)

72.       Y. Bernadskaya, A. Kuan, A. Tjärnberg, N. Kaplan, M. Failla, K. Wiechecki, P. Zhang, M. Bikou, W. Wang, and L. Christiaen. Cell cycle-driven transcriptome maturation confers multilineage competence to cardiopharyngeal progenitors. 2024. BioRxiv. 2024.07.23.604718. doi: 10.1101/2024.07.23.604718.

71.       Hossain MF, Popsuj S, Vitrinel B, Kaplan NA, Stolfi A, Christiaen L, Ruggiu M. A conserved RNA switch for acetylcholine receptor clustering at neuromuscular junctions in chordatesbioRxiv [Preprint]. 2024 Jul 6:2024.07.05.602308. doi: 10.1101/2024.07.05.602308.

70.       K. Schuster, and L. Christiaen. The Chordate Origins of Heart Regeneration. 2023. BioRxiv. 2023.09.19.558507; doi: https://doi.org/10.1101/2023.09.19.558507

 

Publications (peer-reviewed, reverse chronological order).

69.       B. T. Mathiesen#, M. Ohta#, B. P. De Magalhaes, C. Castelletti, V. Perria, L. Christiaen* and N. Ohta*. A simple inland culture system provides insights into ascidian post-embryonic developmental physiologyOpen Biol. 2025 Jan;15(1):240340. doi: 10.1098/rsob.240340. 

68.       Naoyuki Ohta, and Lionel Christiaen. Cellular remodeling and JAK inhibition promote zygotic gene expression in the Ciona germline. 2024. EMBO Rep. 2024 May;25(5):2188-2201. doi: 10.1038/s44319-024-00139-0. Epub 2024 Apr 22. 

67.       A. Tjärnberg, M. Beheler-Amass, C.A. Jackson, L.A. Christiaen, D. Gresham, R. Bonneau, Structure Primed Embedding on the Transcription Factor Manifold Enables Transparent Model Architectures for Gene Regulatory Network and Latent Activity Inference. 2023. Genome Biol 2024 Jan 18;25(1):24. doi: 10.1186/s13059-023-03134-1. BioRxiv. 2023.02.02.526909.

66.       Burcu Vitrinel, Christine Vogel, Lionel Christiaen. Rnf149-related is an FGF/MAPK-independent regulator of pharyngeal muscle fate specification. 2023. Int J Mol Sci. 24(10):8865. doi: 10.3390/ijms24108865. BioRxiv 2022.01.07.475354; doi: https://doi.org/10.1101/2022.01.07.475354

65.       Song M, Yuan X, Racioppi C, Leslie M, Stutt N, Aleksandrova A, Christiaen L, Wilson MD, Scott IC. GATA4/5/6 family transcription factors are conserved determinants of cardiac versus pharyngeal mesoderm fate. 2022. Sci Adv. doi: 10.1126/sciadv.abg0834. PMCID: PMC8916722.

64.       Bernadskaya YY, Yue H, Copos C, Christiaen L, Mogilner A. Supracellular organization confers directionality and mechanical potency to migrating pairs of cardiopharyngeal progenitor cells. 2021. Elife. doi: 10.7554/eLife.70977. PubMed PMID: 34842140; PMCID: PMC8700272.

63.       Nomaru H, Liu Y, De Bono C, Righelli D, Cirino A, Wang W, Song H, Racedo SE, Dantas AG, Zhang L, Cai CL, Angelini C, Christiaen L, Kelly RG, Baldini A, Zheng D, Morrow BE. Single cell multi-omic analysis identifies a Tbx1-dependent multilineage primed population in murine cardiopharyngeal mesoderm. 2021. Nat Commun. 12(1):6645. doi: 10.1038/s41467-021-26966-6. PMCID: PMC8599455.

62.       Tjärnberg, A., Omar Mahmood, Christopher A Jackson, Giuseppe-Antonio Saldi, Kyunghyun Cho, Lionel Christiaen, Richard Bonneau. Optimal tuning of weighted kNN- and diffusion-based methods for denoising single cell genomics data. 2021. PLOS Computational Biology 17 (1), e1008569

61.       Elijah K Lowe, Claudia Racioppi, Nadine Peyriéras, Filomena Ristoratore, Lionel Christiaen, Billie J Swalla, Alberto Stolfi. A cis‐regulatory change underlying the motor neuron‐specific loss of Ebf expression in immotile tunicate larvae. 2020. Evolution & Development, e12364

60.       Woo Jun Shim, Enakshi Sinniah, Jun Xu, Burcu Vitrinel, Michael Alexanian, Gaia Andreoletti, Sophie Shen, Brad Balderson, Guangdun Peng, Naihe Jing, Yuliangzi Sun, Yash Chhabra, Yuliang Wang, Patrick P L Tam, Aaron Smith, Michael Piper, Lionel Christiaen, Quan Nguyen, Mikael Bodén, Nathan J. Palpant. Comparative analysis of diverse cell states establishes an epigenetic basis for inferring regulatory genes governing cell identity. 2020. Cell Systems 11 (6), 625-639. e13.

59.       Vitrinel, B., Dylan E. Iannitelli, Esteban O. Mazzoni, Lionel Christiaen, Christine Vogel. Simple method to quantify protein abundances from 1000 cells. ACS Omega. 2020. Doi: 10.1021/acsomega.0c01191. 

58.       Ohta, N., Ng, J.T., Kaplan, N., Gravez, B.J., and Lionel Christiaen. Asymmetric Fitness of Second-Generation Interspecific Hybrids Between Ciona robusta and Ciona intestinalis. G3 (Bethesda). 2020 Jun 9;g3.401427.2020. PMCID: PMC7407461 doi: 10.1534/g3.120.401427. 

57.       Racioppi, C., Wiechecki, K.A., and L. Christiaen. Combinatorial chromatin dynamics foster accurate cardiopharyngeal fate choices. 2019, Elife. Nov 20;8. pii: e49921. doi: 10.7554/eLife.49921. PMID: 31746740 PMCID: PMC6952182 DOI: 10.7554/eLife.49921

56.       Prummel, K., Hess, C., Nieuwenhuize, S., Parker, H., Rogers, K.W., Kozmikova, I., Racioppi, C., Burger, S., Brombacher, E.C., Burger, A., Felker, A., Chiavacci, E., Shah, G., Huisken, J., Kozmik, Z., Christiaen, L., Mueller, P., Bronner, M., Krumlauf, R., and C. Mosimann. A conserved regulatory program drives emergence of the lateral plate mesoderm. Nat Commun, 2019, 10(1):3857. doi: 10.1038/s41467-019-11561-7. 

55.       Wang, W., Niu, X., Stuart, T., Jullian, E., Mauck, W., Kelly, R., Satija, R.*, and L. Christiaen*. A single cell transcriptional roadmap for cardiopharyngeal fate diversification. Nat Cell Biol, 2019, 21(6):674-686. doi: 10.1038/s41556-019-0336-z. (* co-corresponding authors). 

54.       Athanasiadou, R., Neymotin, B., Brandt, N., Wang, W., Christiaen, L., Gresham, D., and D. Tranchina. A Complete Statistical Model for Calibration of RNA-seq Counts using External Spike-ins and Maximum Likelihood Theory. PLOS Comp Biol, 2019, 15(3):e1006794. doi: 10.1371/journal.pcbi.1006794.

53.       Kaplan, N., Wang, W., and L. Christiaen. Initial characterization of Wnt-Tcf functions during Ciona heart development. Dev Biol, 2019, pii: S0012-1606(18)30458-5. doi: 10.1016/j.ydbio.2018.12.018.

52.       Racioppi C., Coppola U., Christiaen L., and F. Ristoratore.Transcriptional regulation of Rab32/38, a specific marker of pigment cell formation in Ciona robusta. Dev Biol, 2019 pii: S0012-1606(18)30004-6. doi: 10.1016/j.ydbio.2018.11.013.

51.       Bernadskaya, Y., Gline, S., Brahmbhatt, S., Wang, W., and L. Christiaen. Discoidin-domain receptor coordinates cell-matrix adhesion and collective polarity in migratory cardiopharyngeal progenitors. Nat Commun, 2019, 10(1):57. doi: 10.1038/s41467-018-07976-3. PMCID:PMC6320373; Preprint: bioRxiv. 154880; doi: https://doi.org/10.1101/154880

50.       Razy-Krajka, F., Gravez, B., Nicole Kaplan, Claudia Racioppi, Wei Wang and L. Christiaen. An FGF-driven feed-forward circuit patterns the cardiopharyngeal mesoderm in space and time. eLife, 2018, 7. pii: e29656. doi: 10.7554/eLife.29656. PMCID: PMC5809146

49.       Burguera D, Marquez Y, Racioppi C, Permanyer J, Torres-Méndez A, Esposito R, Albuixech-Crespo B, Fanlo L, D'Agostino Y, Gohr A, Navas-Perez E, Riesgo A, Cuomo C, Benvenuto G, Christiaen LA, Martí E, D'Aniello S, Spagnuolo A, Ristoratore F, Arnone MI, Garcia-Fernàndez J, Irimia M. Evolutionary recruitment of flexible Esrp-dependent splicing programs into diverse embryonic morphogenetic processes. Nat Commun. 2017. 8(1):1799. doi: 10.1038/s41467-017-01961-y.

48.       Brozovic M, Dantec C, Dardaillon J, Dauga D, Faure E, Gineste M, Louis A, Naville M, Nitta KR, Piette J, Reeves W, Scornavacca C, Simion P, Vincentelli R, Bellec M, Aicha SB, Fagotto M, Guéroult-Bellone M, Haeussler M, Jacox E, Lowe EK, Mendez M, Roberge A, Stolfi A, Yokomori R, Brown CT, Cambillau C, Christiaen L, Delsuc F, Douzery E, Dumollard R, Kusakabe T, Nakai K, Nishida H, Satou Y, Swalla B, Veeman M, Volff JN, Lemaire P. ANISEED 2017: extending the integrated ascidian database to the exploration and evolutionary comparison of genome-scale datasets. Nucleic Acids Res. 2018. 46(D1):D718-D725. doi: 10.1093/nar/gkx1108.

47.       Racioppi C, Valoroso MC, Coppola U, Lowe EK, Brown CT, Swalla BJ, Christiaen L, Stolfi A, Ristoratore F. Evolutionary loss of melanogenesis in the tunicate Molgula occulta. EvoDevo, 2017, 8(1). doi: 10.1186/s13227-017-0074-x

46.       Gandhi, S., Razy-Krajka, F., Christiaen, L*, and A. Stolfi*. CRISPR knockouts in Ciona embryos. Adv Exp Med Biol. 2018;1029:141-152. doi: 10.1007/978-981-10-7545-2_13 (* co-corresponding authors). 

45.       Wang, W., Racioppi, C., Gravez, B., and L. Christiaen. Purification of Fluorescent Labelled Cells from Dissociated Ciona Embryos. Adv Exp Med Biol. 2018;1029:101-107. doi: 10.1007/978-981-10-7545-2_9. 

44.       Gandhi, S., Haeussler, M., Razy-Krajka, F., Christiaen, L.*, and A. Stolfi*. Evaluation and rational design of guide RNAs for efficient CRISPR/Cas9-mediated mutagenesis in Ciona. Dev Biol, 2017, 425(1):8-20; doi: 10.1016/j.ydbio.2017.03.003; BioRxiv; doi: http://dx.doi.org/10.1101/041632; * co-corresponding authors). PMCID: PMC5502750

43.       Lam K.Y., Westrick Z.M., Müller C.L., Christiaen L., and R. Bonneau. Fused Regression for Multi-source Gene Regulatory Network Inference. PLoS Comp Biol., 2016, 12(12):e1005157. doi: 10.1371/journal.pcbi.1005157

42.       Tolkin, T., and L. Christiaen. Rewiring of an ancestral Tbx1/10 - Ebf - Mrf network for pharyngeal muscle specification in distinct embryonic lineages. Development, 2016, 143(20):3852-62

41.       Evans-Anderson, H., and L. Christiaen. Ascidians as simple chordate models for heart development and regeneration. J. Cardiovasc. Dev. Dis., 2016, 3(3). pii: 25.

40.       Bernadskaya, Y., and L. Christiaen. Transcriptional control of developmental cell behaviors. Ann Rev Cell Dev Biol, 2016, 32:77-101.

39.       Stolfi, A., Ryan, K., Meinertzhagen, I., and L. Christiaen. Migratory neuronal progenitors arise from the neural plate borders in tunicates. Nature, 2015, 527(7578):371-4.

38.       Kaplan, N., Razy-Krajka, F., and L. Christiaen. Regulation and evolution of cardiopharyngeal cell identity and behavior: insights from simple chordates. Curr Op Gen Dev, 2015,32:119-128.

37.       Diogo, R.*, R. Kelly*, L. Christiaen*, M. Levine, J.M. Ziermann, J. Molnar & E. Tzahor*. A new heart for a new head in vertebrate cardiopharyngeal evolution. Nature, 2015, 520(7548):466-73 (* co-corresponding authors; invited review)

36.       Gline, S., Kaplan, N., Bernadskaya, Y., Abdu, Y., and L.Christiaen. Surrounding tissues canalize motile cardiopharyngeal progenitors towards collective polarity and directed migration. Development, 2015, 142(3):544-54.

35.       Stolfi, A., Gandhi, S., Salek, F., and L.Christiaen. Tissue-specific genome editing in Ciona embryos by CRISPR/Cas9. Development, 2014. 141(21):4115-20. doi: 10.1242/dev.114488.

34.       Stolfi, A., Sasakura, Y., Chalopin, D., Satou, Y., Christiaen, L., Dantec, C., Endo, T., Naville, M., Nishida, H., Swalla, B., Volff, J.-N. , Voskoboynik, A., Dauga, D., Lemaire, P. Guidelines for Nomenclature of Genetic Elements in Tunicate Genomes. Genesis, 2014, 53(1):1-14. doi: 10.1002/dvg.22822

33.       Stolfi, A., Lowe, E., Racioppi, C., Ristoratore, M., Brown, C.T., Swalla, B., and L. Christiaen. Divergent mechanisms regulate conserved cardiopharyngeal development and gene expression in distantly related ascidians. eLife, 2014, 3:e03728. doi: 10.7554/eLife.03728

32.       Racioppi, C., A. K. Kamal, L. Zanetti, F. Razy-Krajka, G. Gambardella, D. di Bernardo, R. Sanges, L. Christiaen* and F. Ristoratore* (* co-corresponding authors). Fibroblast growth factor signalling controls nervous system patterning and pigment cell formation in Ciona intestinalis. Nat Commun, 2014, 5:4830.

31.       Razy-Krajka, F., K. Lam, W. Wang, E. Siu, A. Stolfi, R. Bonneau, and L. Christiaen. Collier/Olf/EBF-dependent transcriptional dynamics control pharyngeal muscle specification from primed cardiopharyngeal progenitors. Dev Cell, 2014, 29(3):263-76.

30.       Wang, W., Razy-Krajka, F., Siu, E., Ketcham, A., and L. Christiaen, NK4 Antagonizes Tbx1/10 to Promote Cardiac Versus Pharyngeal Muscle Fate in the Ascidian Second Heart Field, PLOS Biology, 2013, 11(12):e1001725

29.       Christiaen, L., Cis-regulatory Timers for developmental Gene Expression, PLOS Biology, 2013, 11(10): e1001698. doi:10.1371/journal.pbio.1001698

28.       Haupaix N., Stolfi A., Sirour C., Picco V., Levine M., Christiaen L., and H. Yasuo, p120RasGAP mediates ephrin/Eph-dependent attenuation of FGF/ERK signals during cell fate specification in ascidian embryos, Development, 2013, 140(21): p. 4347-52

27.       Stolfi, A., and L. Christiaen, Genetic and genomic toolbox of the chordate Ciona intestinalis, Genetics, 2012, 192(1): p. 55-66

26.       Christiaen, L. Developmental Cell Behavior. Semin Cell Dev Biol, 2012, 23: p. 289

25.       Tolkin, T., and L. Christiaen, Development and Evolution of the Ascidian Cardiogenic Mesoderm. Curr Top Dev Biol, 2012. 100: p. 107-42

24.       Wang, W., and L. Christiaen, Transcriptional Enhancers in Ascidian Development. Curr Top Dev Biol, 2012. 98: p. 147-72.

23.       Tassy, O., D. Dauga, F. Daian, D. Sobral, F. Robin, P. Khoueiry, D. Salgado, V. Fox, D. Caillol, R. Schiappa, B. Laporte, A. Rios, G. Luxardi, T. Kusakabe, J.S. Joly, S. Darras, L. Christiaen, M. Contensin, H. Auger, C. Lamy, C. Hudson, U. Rothbacher, M.J. Gilchrist, K.W. Makabe, K. Hotta, S. Fujiwara, N. Satoh, Y. Satou, and P. Lemaire, The ANISEED database: digital representation, formalization, and elucidation of a chordate developmental program. Genome Res, 2010. 20(10): p. 1459-68.

22.       Stolfi, A., T.B. Gainous, J.J. Young, A. Mori, M. Levine, and L. Christiaen, Early chordate origins of the vertebrate second heart field. Science, 2010. 329(5991): p. 565-8.

21.       Haeussler, M., Y. Jaszczyszyn, L. Christiaen, and J.S. Joly, A cis-regulatory signature for chordate anterior neuroectodermal genes.PLoS Genet, 2010. 6(4): p. e1000912.

20.       Christiaen, L., A. Stolfi, and M. Levine, BMP signaling coordinates gene expression and cell migration during precardiac mesoderm development. Dev Biol, 2010. 340(2): p. 179-87.

19.       Christiaen, L., E. Wagner, W. Shi, and M. Levine, The sea squirt Ciona intestinalis. CSH Protoc, 2009. 2009(12): p. pdb emo138.

18.       Christiaen, L., E. Wagner, W. Shi, and M. Levine, Isolation of sea squirt (Ciona) gametes, fertilization, dechorionation, and development.CSH Protoc, 2009. 2009(12): p. pdb prot5344.

17.       Christiaen, L., E. Wagner, W. Shi, and M. Levine, Electroporation of transgenic DNAs in the sea squirt Ciona. CSH Protoc, 2009. 2009(12): p. pdb prot5345.

16.       Christiaen, L., E. Wagner, W. Shi, and M. Levine, X-gal staining of electroporated sea squirt (Ciona) embryos. CSH Protoc, 2009. 2009(12): p. pdb prot5346.

15.       Christiaen, L., E. Wagner, W. Shi, and M. Levine, Microinjection of morpholino oligos and RNAs in sea squirt (Ciona) embryos. CSH Protoc, 2009. 2009(12): p. pdb prot5347.

14.       Christiaen, L., E. Wagner, W. Shi, and M. Levine, Whole-mount in situ hybridization on sea squirt (Ciona intestinalis) embryos. CSH Protoc, 2009. 2009(12): p. pdb prot5348.

13.       Christiaen, L., E. Wagner, W. Shi, and M. Levine, Isolation of individual cells and tissues from electroporated sea squirt (Ciona) embryos by fluorescence-activated cell sorting (FACS). CSH Protoc, 2009. 2009(12): p. pdb prot5349.

12.       Christiaen, L., A. Stolfi, B. Davidson, and M. Levine, Spatio-temporal intersection of Lhx3 and Tbx6 defines the cardiac field through synergistic activation of Mesp. Dev Biol, 2009. 328(2): p. 552-60.

11.       Christiaen, L., B. Davidson, T. Kawashima, W. Powell, H. Nolla, K. Vranizan, and M. Levine, The transcription/migration interface in heart precursors of Ciona intestinalis. Science, 2008. 320(5881): p. 1349-52.

10.       Christiaen, L., Y. Jaszczyszyn, M. Kerfant, S. Kano, V. Thermes, and J.S. Joly, Evolutionary modification of mouth position in deuterostomes. Semin Cell Dev Biol, 2007. 18(4): p. 502-11.

9.         Beh, J., W. Shi, M. Levine, B. Davidson, and L. Christiaen, FoxF is essential for FGF-induced migration of heart progenitor cells in the ascidian Ciona intestinalis. Development, 2007. 134(18): p. 3297-305.

8.         Davidson, B., W. Shi, J. Beh, L. Christiaen, and M. Levine, FGF signaling delineates the cardiac progenitor field in the simple chordate, Ciona intestinalis. Genes Dev, 2006. 20(19): p. 2728-38.

7.         Davidson, B. and L. Christiaen, Linking chordate gene networks to cellular behavior in ascidians. Cell, 2006. 124(2): p. 247-50.

6.         Tiozzo, S., L. Christiaen, C. Deyts, L. Manni, J.S. Joly, and P. Burighel, Embryonic versus blastogenetic development in the compound ascidian Botryllus schlosseri: insights from Pitx expression patterns. Dev Dyn, 2005. 232(2): p. 468-78.

5.         Moret, F., L. Christiaen, C. Deyts, M. Blin, P. Vernier, and J.S. Joly, Regulatory gene expressions in the ascidian ventral sensory vesicle: evolutionary relationships with the vertebrate hypothalamus. Dev Biol, 2005. 277(2): p. 567-79.

4.         Moret, F., L. Christiaen, C. Deyts, M. Blin, J.S. Joly, and P. Vernier, The dopamine-synthesizing cells in the swimming larva of the tunicate Ciona intestinalis are located only in the hypothalamus-related domain of the sensory vesicle. Eur J Neurosci, 2005. 21(11): p. 3043-55.

3.         Christiaen, L., F. Bourrat, and J.S. Joly, A modular cis-regulatory system controls isoform-specific pitx expression in ascidian stomodaeum. Dev Biol, 2005. 277(2): p. 557-66.

2.         Hendrickson, C., L. Christiaen, K. Deschet, D. Jiang, J.S. Joly, L. Legendre, Y. Nakatani, J. Tresser, and W.C. Smith, Culture of adult ascidians and ascidian genetics. Methods Cell Biol, 2004. 74: p. 143-70.

1.         Christiaen, L., P. Burighel, W.C. Smith, P. Vernier, F. Bourrat, and J.S. Joly, Pitx genes in Tunicates provide new molecular insight into the evolutionary origin of pituitary. Gene, 2002. 287(1-2): p. 107-13.