Genetic control of cell morphogenesis during Drosophila melanogaster cardiac tube formation.

Tubulogenesis is an essential component of organ development, yet the underlying cellular mechanisms are poorly understood. We analyze here the formation of the Drosophila melanogaster cardiac lumen that arises from the migration and subsequent coalescence of bilateral rows of cardioblasts. Our study of cell behavior using three-dimensional and time-lapse imaging and the distribution of cell polarity markers reveals a new mechanism of tubulogenesis in which repulsion of prepatterned luminal domains with basal membrane properties and cell shape remodeling constitute the main driving forces.

In vitro migration assays of neural stem cells.

We describe three rapid procedures for the in vitro investigation of molecular factors influencing the migration of neural precursors derived from embryonic or postnatal neural stem cells. In the first assay, factors influencing chain migration from the anterior subventricular zone of perinatal mice can be analyzed after explantation and embedding in Matrigel, a three-dimensional substrate mimicking the in vivo extracellular matrix. The second assay enables to assess soluble factors influencing radial migration away from adherent neurospheres in which embryonic stem cells have been expanded.

Control of planar divisions by the G-protein regulator LGN maintains progenitors in the chick neuroepithelium.

The spatio-temporal regulation of symmetrical as opposed to asymmetric cell divisions directs the fate and location of cells in the developing CNS. In invertebrates, G-protein regulators control spindle orientation in asymmetric divisions, which generate progeny with different identities. We investigated the role of the G-protein regulator LGN (also called Gpsm2) in spindle orientation and cell-fate determination in the spinal cord neuroepithelium of the developing chick embryo.