Zebrafish is a freshwater fish that serves as a great model organism to cell and developmental biologists. During development, cells undergo dramatic reorganization during formation of the central nervous system, a process called neurulation. A recent paper describes the interaction between two proteins, called Protocadherin-19 and N-cadherin, and how these two proteins regulate cell movements during neurulation. These proteins together regulate cell-cell adhesion at a time when cells converge together to form a midline seam in the neural plate, a key feature of brain development. Images above are cell trajectories taken from time-lapse series of zebrafish embryos undergoing neurulation. The trajectories of cells in a normal embryo (top left) show a convergence of cells to the midline and a general movement of cells in one direction. Cells showed compromised movement in embryos with low levels of either protocadherin-19 (top, right), N-cadherin (bottom, left), or both (bottom, right).
BONUS!! Cool movies of two-photon image sequences can be found here.