Chemotaxis and morphogen dynamics in biological tissues
In developmental biology patterns formed by morphogens are often affected by movement of cells producing the morphogens. The mutual effects of cell movement and dynamics of concentration patterns are enhanced when the movement is due to chemotactic response to the morphogens. Here we present a set of cell movement patterns with associated patterns in concentration fields of chemotactic agents obtained analytically in continuous model and numerically in individual-cell based model. We have found that group of cells can push itself to move, provided that it produces a chemical which acts as a chemorepellent to its constituent cells. Also the group of cells can be pulled to move by the chemoattractor produced by the surrounding cells in a tissue. Many other chemotactic scenarios are in play when the group of cells is inhomogeneous, i.e. when only part of cells is reacting chemotactically to the morphogen produced by the other part or in the surrounding tissue. We demonstrate the se scenarios on the models of primitive streak extension and regression in the chick embryo.