Title:

Cellular dynamism during secondary neurulation in the forming tail

 

Speaker:
Yoshiko Takahashi
(Department of Zoology, Graduate School of Science, Kyoto University)

 

Abstract:
　The tail is an important part of the boy that most characterizes the vertebrate. The tail also allows a variety of diversities because in many cases tails are specified to particular purposes of habitation (e. g. long vs short tails, decorative appealing for reproductive tactics). The tail, forming posteriorly to the hind limb/anus level, consists of two major components: the ectoderm (nervous system) and mesoderm (muscles and bones). For such formation, the tail bud, a mass of mesenchymal cells, plays critical roles. In particular, the tail bud cells that participate in the neural tube formation undergo EMT and MET, and this process is called secondary neurulation (SN), the process completely different from the well-known neural plate folding seen in the anterior body. Using chickens, we have recently identified the presumptive SN region located posteriorly to Hensen’s node in stage 8 chicken embryo (equivalent to ~E8 mouse embryo). Importantly, this region does not contribute to the mesodermal components. Thus, neural tube-forming cells and mesodermal cells are segregated early in the tail-forming region, in which Sox 2 plays important roles. Furthermore, SN-forming precursors behave as stem cell-like cells. We will discuss the roles of SN in both embryogenesis and evo-devo.