Regulation of Both Cell State and Gene Expression with Nutrient Gradient as Conserved Mechanism Differentiating the Cell Fates for Embryonic Gastrulation: A Theory

Abstract

In this article, it is newly suggested the regulation from nutrient gradient on both cell metabolic state and expressional gene classes as the conserved mechanism differentiating the cell fates for formation of the three germ layers of gastrula in animals. As a new theory, it is supported by the totipotency and pluripotency of early embryonic cells and cultured stem cells to be regulated by nutrients, as well as by the universal formation of nutrient gradient during gastrulation in various animals. Besides, it is also supported by the subsequent phenotypic fates of three germ layers of gastrula, with the endoderm manifesting expression of gene classes in nutritious condition and giving rise to the epithelium of digestive and respiratory system; the ectoderm manifesting expression of gene classes with nutrient dependence and environmental effect, and giving rise to the nervous and epithelial tissues; the mesoderm lying between them and giving rise to the muscle and adipose. Likewise, it is directly supported by the different nutrient effects onto such trilaminar differentiation in various cultured stem cells. Finally, it is in further supported by the evolutionary effects of nutrients in preserving the trilaminar fates in gastrula versus relative permitting the variations in anteroposterior determination. Conclusively, it is identified the nutrient gradient as an important mechanism to partially differentiate the cell fates for embryonic gastrulation.