Neural Crest Induction
The cellular and molecular mechanisms that control neural crest induction are only just beginning to be unraveled. Several laboratories, including our own, have been studying the process of neural crest induction and as a result, the following model has emerged.
Neural Crest induction model
The process begins with induction of the neural plate and its border, mediated, at least in part, by inhibition of BMP signaling. Strong inhibition of BMP leads to neural plate specification, while weaker inhibition specifies the neural plate border (A). Interactions between the neural plate and the epidermis have been able to recreate this intermediate level of BMP activity required for the specification of the neural plate border.
Additional signals (Wnts, FGFs or retinoic acid) from the posterior part of the embryo, the paraxial mesoderm or the epidermis are required to specify the precise region of the neural plate border that will form the neural crest cell population (B). This model of neural crest induction has been generated from data obtained in different organisms including Xenopus, zebrafish and chick.
Although many inductive tissues and molecules have been identified we still do not have a clear picture how the Neural Crest are induced in a particular region of the ectoderm and at a particular time.
Aim: temporal and spatial induction of the Neural Crest
We are interested in analyzing the temporal and spatial induction of the Neural Crest. We would like to know whether there is a sequence of steps in which the different inductive signals work at different times, or they work together at the same time to induce Neural Crest. If so, how are these signals integrated? Where are the signals produced from?
Classical embryological techniques and modern molecular biology are used for this project. To analyze this problem we perform dissection and grafts of different tissues, overexepression of different signals and dominant negatives of their receptors in the embryos. Experiments are performed in Xenopus and zebrafish embryos.