Mechano-sensing in Embryonic Biochemical and Morphologic Patterning: Evolutionary Perspectives in the Emergence of Primary Organisms

Abstract

Embryogenesis involves biochemical patterning as well as mechanical morphogenetic movements, both regulated by the expression of the regulatory genes of development. The reciprocal interplay of morphogenetic movements with developmental gene expression is becoming an increasingly intense subject of investigation. The molecular processes through which differentiation patterning closely regulates the development of morphogenetic movements are today becoming well understood. Conversely, experimental evidence recently revealed the involvement of mechanical cues due to morphogenetic movements in activating mechano-transduction pathways that control both the differentiation and the active morphogenesis of fundamental events in embryonic tissue development. Here I will first focus on the central role the shape of biological structures of the molecular and mesoscopic cell scales plays in mechano-transduction. Then, after a short description of the genetic regulation of the Drosophila embryo mesoderm invagination at gastrulation—one of the best-understood morphogenetic movement of embryogenesis—I will detail the processes of differentiation and of active morphogenesis of Drosophila embryo gastrulation, which require mechano-transduction. Finally, I will explore the putative consequences in evolution of these mechano-transduction events. I speculate that the first ancient multicellular organisms might have emerged from primary morphological and differentiation patterns induced by primitive mechano-sensation effects allowed by mechano-transduction in response to their physical environment, such as touch by gravity or water flows, which might have acted as primitive motor–sensorial systems, thus conditioning the emergence of our primary animal ancestors.