A research by the Spanish National Research Council (CSIC) (Spain), in which the Complutense University of Madrid and Univesity College London have collaborated, has discovered a communication mechanism between chicken embryo cells through chemical signals that make possible the differentiation between its different parts. It is a process in which a fundamental event is produced, such as the breaking of the radial symmetry of the embryo, so that it acquires the spatial coordinates that determine where the right and left sides, the ventral and dorsal parts, are distributed later. or the head and tail of the embryo. The study has just been published in the Scientific Reports journal.
Once the cell has been fertilized, begins a process of cell division by which it becomes an embryo with thousands of cells. All this transformation occurs in a short period of time: “When they reach this point of embryonic development, the cells are still equivalent since they all maintain the potential to give rise to the tissues that make up the organism,” says Federica Bertocchini, researcher of the CSIC in the Institute of Biomedicine and Biotechnology of Cantabria. “But, little by little,” she assures, “each loses this potentiality and acquires a particular destiny that will lead her to become, for example, a kidney, heart or brain cell.”
The research work in which Clemente Arias, Miguel Herrero and Claudio Sterna have also collaborated, has found that the breaking of radial symmetry occurs at a very early stage, even before the spatial coordinates distribute the body parts. The cells of the early embryo communicate with each other through chemical signals (called BMP4 and Vg1). Although initially the cells produce both BMP4 and Vg1, as the embryo develops, some begin to produce only one or the other, depending on their position in the embryo.
“Within a few hours two zones are clearly differentiated in the embryo, one where only BMP4 is expressed, and another where only Vg1 appears, which, in turn, will be the anterior and posterior poles of the embryo respectively,” Bertocchini adds.
In order to know how cells that in principle are similar produce one or another chemical signal, expressing themselves in opposite poles, the researchers worked with mathematical and experimental models: “We have worked with chicken because it is one of the model animals in the study of the embryonic development of the amniotas (mammals, birds and reptiles) “, clarifies the researcher.
The most used mathematical models in embryology are those known as reaction-diffusion models. These models are capable of reproducing the spatial patterns observed in many biological systems. However, its drawback is that they are based on physical or chemical mechanisms. Therefore, researchers have proposed an alternative model: “This work is based on biological mechanisms that take place in the cells of the embryo. Both BMP4 and Vg1 bind to specific receptors in the membrane of cells, which triggers processes that activate or inactivate the production of BMP4 or Vg1. In this way the behavior of each cell is conditioned by that of its neighbors, “says Bertocchini.
This model explores the consequences of this biological mechanism in the cells of the embryo and explains, in turn, the breaking of the initial symmetry, with the consequent formation and distribution of the different parts of the embryo.