Development of tools to study molecular mechanisms of neural circuit formation

Classical genetic studies in mouse do not allow for the precise temporal control of loss of gene function during embryonic development. Therefore, we have developed in ovo RNAi, a method that allows us to silence genes in a precisely timed manner during development of the embryonic chicken spinal cord. We are refining this tool and transferring it to other areas of the central but also the peripheral nervous system. For example, ex ovo RNAi can be used to study the molecular mechanisms of axon guidance in the developing cerebellum.

Tissue clearing and light-sheet microscopy (mesoSPIM) allow for visualization of neural circuits in the intact embryo. In contrast to tissue sections or organotypic slices, whole-mount preparations of the brain or the peripheral nervous system provide a rapid overview on neural circuits without the interference of cutting angle or experimentally induced distortion.
Ideally, axons can be followed during navigation using in vivo live imaging. The comparison of axonal behavior at choice points between experimental and control-treated embryos provides clues on the mechanisms of axon navigation.

Key Publications:

Tsapara G, Andermatt I, and Stoeckli ET. (2020) Gene Silencing in Chicken Brain Development.
Methods Mol Biol. 2047:439-456. doi:10.1007/978-1-4939-9732-9_25.

Voigt FF, Kirschenbaum D, Platonova E, Pagès S, Campbell RAA, Kastli R, Schaettin M, Egolf L, van der Bourg A, Bethge P, Haenraets K, Frézel N, Topilko T, Perin P, Hillier D, Hildebrand S, Schueth A, Roebroeck A, Roska B, Stoeckli ET, Pizzala R, Renier N, Zeilhofer HU, Karayannis T, Ziegler U, Batti L, Holtmaat A, Lüscher C, Aguzzi A, and Helmchen F. (2019) The mesoSPIM initiative: open-source light-sheet microscopes for imaging cleared tissue. Nat Methods. doi: 10.1038/s41592-019-0554-0.

Wilson NH and Stoeckli ET. (2012) In ovo electroporation of miRNA-based plasmids in the developing neural tube and assessment of phenotypes by DiI injection in open-book preparations.
J Vis Exp. pii: 4384. doi: 10.3791/4384.

Wilson NH and Stoeckli ET. (2011) Cell type specific, traceable gene silencing for functional gene analysis during vertebrate neural development.
Nucleic Acids Res. 39:e133. doi: 10.1093/nar/gkr628.

Baeriswyl T and Stoeckli ET. (2008) Axonin-1/TAG-1 is required for pathfinding of granule cell axons in the developing cerebellum.
Neural Dev. 3:7. doi: 10.1186/1749-8104-3-7.

Pekarik V, Bourikas D, Miglino N, Joset P, Preiswerk S, and Stoeckli ET. (2003) Screening for gene function in chicken embryo using RNAi and electroporation.
Nat Biotechnol. 21(1):93-6.