Christian Mosimann

The Mosimann Lab is moving!

Starting Summer 2019, the Mosimann Lab will be located at the University of Colorado Denver, School of Medicine.
Dr. Christian Mosimann is appointed Johnson Endowed Chair in Heart Development Research and Associate Professor, and Dr. Alexa Burger as Research Associate Professor. We'll join the growing Anschutz Medical Campus community and its developmental biology and cardiology labs with our zebrafish (and chickens, et al).

Postdoc, PhD, and PRA/tech positions available (look for official ads and announcements). Rocky Mountains, here we come!

UC Denver SOM


Research: Cell fate control in vertebrate development

The aim of my lab's research is to understand how cells acquire their fates during development. As principal model, we use the zebrafish (Danio rerio) to investigate the cell fate control of mesodermal lineages, in particular of the Lateral Plate Mesoderm (LPM). Our work combines transgenic, genome editing, cross-species analysis of cis-regulatory elements, and latest imaging techniques. We in particular love enhancers!
Some of our key questions:

1) What is the developmental and evolutionary origin of the cardiovascular system?

2) How can the LPM form its vast spectrum of downstream cell fates?

3) What mutations and defective mechanisms cause human congenital defects in LPM-derived organ systems?

Lateral Plate Mesoderm: the forgotten mesoderm

Zebrafish LPM
Lateral plate mesoderm (LPM) visualized in a zebrafish embryo with fluorescent transgenic reporter.

In vertebrates, the organ precursors for the heart, blood, endothelium, kidney, and limb connective tissue arise in close proximity from distinct territories within the LPM at the periphery of the embryo. The principles driving the LPM into its dramatically different cell fates must be of ancient evolutionary origin. The molecular mechanisms that divide lateral territories along the embryonic axis into their different organ cell fates remain nonetheless poorly understood. More in-depth knowledge about the mechanisms of LPM fate control is critical to our understanding of the vertebrate body plan and causes of congenital cardiovascular disorders, to therapeutic drug discovery, and to improve the targeted manipulation of embryonic stem (ES) or induced pluripotent stem (iPS) cells into sought-after regenerative cell types.

Our experiments apply spatio-temporally controlled lineage tracing and genetic perturbations via Tamoxifen-inducible Cre/lox transgenics and CRISPR-Cas9 genome editing to elucidate the mechanisms of earliest cardiovascular and general LPM lineage patterning. For imaging, we routinely apply SPIM/lightsheet imaging to capture the developing embryo in toto. Parallel approaches apply discovery of novel cis-regulatory elements, functional studies of novel candidate genes, and live imaging to identify novel molecular components of LPM patterning and its descendant cell lineages.

We combine our zebrafish work with reporter assays in chick embryos and in collaboration also expand our studies to other model systems. We also continue to refine genetic lineage tracing techniques and genome engineering in the zebrafish and beyond.

Mechanisms of chordoma formation and mesodermal tumors

Zebrafish chordoma
Chordoma in a zebrafish embryo, histological preparation.

Chordoma is a rare, slow-growing tumor that arises from remnant cells of the notochord, a collagen-secreting embryonic structure that normally regresses before birth. Treatment remains difficult due to the delicate surgical removal and radiation/chemo resistance of chordoma. Chordoma genomes predominantly feature deletions and amplifications, including of the T/Brachyury gene and of several RTK loci; the causative impact of these mutations remains undetermined. Brachyury is a developmental T-box transcription factor that drives mesodermal cell fates and EMT. Its expression is controlled by an incompletely charted program that includes feedback loops with RTK/Ras-relayed pathways. The lack of a suitable genetic model has previously hampered efforts to study the genetic causes, the mechanisms of tumor onset, and effective therapeutic interventions.

  Our chordoma and cancer endeavors are led by Dr. Alexa Burger in the lab. To study chordoma in vivo, we leverage our expertise in transgenic tumor modelling and our recently established first animal model for chordoma in zebrafish. The zebrafish embryo provides a potent model for chordoma formation: zebrafish chordomas rapidly form within 3-5 days in developing notochord cells upon oncogenic transformation. The resulting tumors share extensive histo-pathological features with human chordoma, providing a potent platform for genetic and chemical compound testing. By combining transgenic and genome editing approaches, we now aim to clarify the unknown tumorigenic mechanisms in chordoma and other secretory cell-based cancers.

Funding Sources

Funding Sources


  • since Summer 2019 - present: Associate Professor, Johnson Endowed Chair in Heart Development Research, University of Colorado Denver, School of Medicine, Dept. of Pediatrics; Denver, USA.
  • 2013-2019:
    SNSF/SNF Assistant Professor/Assistant Professor, IMLS, UZH; Zürich, Switzerland.
  • 2008-2013:
    Postdoctoral research fellow  with Leonard Zon, MD, HHMI/Boston Children's Hospital/Harvard Medical School; Boston, USA.
    EMBO Long-term Fellowship (2008-2009).
    HFSP Long-term Fellowship (2009-2012).
    SNSF/SNF Advanced Researcher Fellowship (2012-2013).
    NIH NI-DDK K99/R00 (2012).
  • 2004-2008:
    Ph. D. in Molecular Biology, with Konrad Basler, PhD, Instiute of Molecular Biology, UZH; Zürich, Switzerland.
  • 1999-2003:
    Diploma in Molecular Biology, Biochemical Immunology, Chemical Physics, UZH; Zürich, Switzerland.