Участие МАР-киназного сигналинга в спецификации клеточных линий и дорсовентральной оси у примитивной гастроподыTestudinalia testudinalis(Patellogastropoda, Mollusca)

Abstract

In Spriralia, the specification of cell lines in the course of development is provided by maternal factors. However, recent studies demonstrated the importance of inductive processes whose significant element is cellular signaling. Our data allow us to speak of the dependent specification of a number of cell lines at the early stages of development of the mollusk Testudinalia testudinalis (Testudinalia tessellate, Patellogastropoda), including the period when the determination of the 3D cell takes place, which is accompanied by a change in the shape and establishing of contacts with animal micromeres by one of the macromeres of the third quartet. It is exactly at this moment that activation of MARK was registered in the 3D blastomere-organizer. An analysis of the influence of the U0126 blocker of the MAP-kinase way on the development of Testudinalia showed that the greatest effect of the inhibitor is observed during the cultivation of embryos until the sixth cycle of fragmentation. It should be noted that a scale of correlation of the degree of defects and increase in concentration exists. Absence of the functioning retractor, disorganization of the muscle system, and abnormal structure of the shell (to the extent of complete absence of the shell), as well as velum, foot, and mantle fold, were observed in a considerable part of larvae after a lengthy upkeep of the objects in the U0126 solution. At the same time, none of the experiments showed a complete disruption of the specification of the dorsoventral axis, which produces a larva with a four-ray radial symmetry. This attests in favor of the existence of various molecular mechanisms of determination of the secondary body axis among the animals from the group Spiralia.