Title:
Tissue dynamics during early Xenopus development

Naoto Ueno
National Institute for Basic Biology

Abstract:
Tissue-tissue interactions during development are essential not only for embryonic inductions but also for mechanical tissue remodeling that ensures organ morphogenesis. We previously reported that tissue-tissue interaction particularly between axial mesoderm and lateral mesoderm is important to establish planar cell polarity in axial mesoderm that enables convergence of the cells from the observations with in vitro tissue recombination assay and that physical contact between axial mesoderm and lateral mesoderm/ectoderm triggers intracellular calcium transient in axial mesoderm. We also reported that P2Y11, a prinergic receptor implicated in mechano-sensing is required for the calcium transient. As one of the ligands for P2Y11 is ATP and ATP is secreted responding to mechanical stresses such as suckling of mammary gland and shear stress in blood vessels, we speculate that extracellular ATP plays essential roles in tisuue-tissue interaction during embryogenesis. Thus, we are currently investigating how extracellular ATP contributes to early development for example by depleting ATP by apyrase (adenosine diphosphatase) that catalyzes the hydrolysis of ATP.
Aside from the tissue interaction for establishing cell polarity in early axial mesoderm, embryonic cells undergo drastic change in shape and global tissue reorganization during early development such as gastrulation and neural tube formation. We are currently challenging to clarify the possible contributions of physical environments including mechanical forces to regulate those processes taking advantage of recent bio-imaging techniques. I will introduce some of our ongoing attempts in the seminar.

References:
Tissue-Tissue interaction: Shindo, A. et al. PLoS ONE 2008

Calcium transient: Shindo, A. et al. PLoS ONE 2010

Neural tube closure, Cell adhesion: Morita, H. et al. Development 2010

Neural tube closure, Microtubules: Suzuki, M. et al. Development 2010

Neural tube closure, Non-neural ectoderm: Morita, H. et al. Development 2012