A complicated interplay between genes, RNA molecules, and proteins is required for the initial cell to grow into a full creature. The mother first exerts indirect control over this process. The GRIF-1 protein controls when the progeny cut themselves off from this influence and begin their own route of development. In the journal Science Advances, a study team from Martin Luther University Halle-Wittenberg (MLU) describes how this procedure functions.
The mother is in charge when a new organism begins to grow. The egg cell and sperm cell combine to create a single new cell during fertilization. However, the mother cell ultimately controls how a new living thing develops and how cell division proceeds. According to geneticist Professor Christian Eckmann from MLU, “Cell division is initially pre-programmed by the mother, regardless of the organism.” The mother’s cell offers a starter set for development that contains the initial proteins as well as the RNA molecules that act as the instructions for subsequent proteins. All of this is required to accelerate cell division and the development of an organism.
Cells cannot access their own genetic material during this first stage, which limits their ability to develop. “Even though the new organism greatly benefits from the maternal input, these parts eventually need to be eliminated.” “Only then will it be able to completely utilize its own genetic material and follow its own growth path,” affirms Eckmann. Germ cells, which grow into gametes, undergo this process considerably later than do somatic cells, which give rise to all of the other cells in the body. “There are many ways for cells to exterminate things.” “You have to work for longevity,” affirms Eckmann. So-called poly-A polymerases give the mother’s short-lived RNA molecules a form of protective cap to prolong their life in germ cell precursors.
Eckmann’s team has uncovered the molecular mechanisms behind the process of cord cutting in germ cells through investigations using the model organism C. elegans. Cells begin making the GRIF-1 protein at a specific stage. The maternal RNA provides the instructions for this procedure. The maternal poly-A polymerases are sought after by the protein as soon as it is created, and it binds to them and attaches a kind of marker to them. According to Eckmann, “GRIF-1 uses it as a flag to designate which maternal proteins are to be destroyed.” This causes a domino effect, as once the poly-A polymerases are killed, they are unable to add new protective caps on maternal RNA molecules, shielding them from degradation and preventing the synthesis of new maternal proteins. “All maternal RNA molecules and proteins eventually disappear. “The germ cell is given complete access to its genetic material and is able to carry out independent growth.” Finally, Eckmann says It is still unknown how the cell determines that it must generate GRIF-1 and activate its own genetic material.
In addition, the genetic material in the germ cells is transmitted to the offspring via the sperm or egg; therefore, the lengthy maternal control procedure has a purpose. It must therefore be preserved as accurately and completely as feasible. The degradation process was intentionally stopped in C. elegans in the lab by Eckmann’s researchers. “Many issues arise when this procedure is interrupted.” “The worms’ offspring become more and more sterile with each generation as the germline is unable to develop robustly,” affirms Eckmann.
Within the scope of the Research Training Group “GRK 2467: Intrinsically Disordered Proteins—MMolecular Principles, Biological Roles, and Illnesses,” the work was funded by the German Research Foundation.
