| 1. |
Yoshiko Takahashi, Yuki Sato, Rinako Suetsugu, Yukiko Nakaya, Mesenchymal-to-epithelial transition during somitic segmentation
A novel approach to studying the roles of Rho family GTPases in morphogenesis, Cells Tissues Organs, 10.1159/000084507, 2005, During early development in vertebrates, cells change their shapes dramatically both from epithelial to mesenchymal and also from mesenchymal to epithelial, enabling the body to form complex tissues and organs. Using somitogenesis as a novel model, Rho family GTPases have recently been shown to play essential and differential roles in individual cell behaviors in actual developing embryos. Levels of Cdc42 activity provide a binary switch wherein high Cdc42 levels allow the cells to remain mesenchymal, while low Cdc42 levels produce epithelialization. Rac1 activity needs to be precisely controlled for proper epithelialization through the bHLH transcription factor Paraxis. Somitogenesis is expected to serve as an excellent model with which one can understand how the functions of developmental genes are resolved into the morphogenetic behavior of individual cells.. |
| 2. |
Yoshiko Takahashi, Yuki Sato, Somitogenesis as a model to study the formation of morphological boundaries and cell epithelialization, Development Growth and Differentiation, 10.1111/j.1440-169X.2008.01018.x, 2008.06, The formation of morphological boundaries between developing tissues is an integral mechanism for generating body forms and functions. For the molecular and cellular studies of how such morphological boundaries form, somitogenesis serves as a particularly good model. When an intersomitic boundary forms in the anterior end of the presomitic mesoderm, cells undergo dynamic behaviors including a separation of tissues and changes in cell shape from mesenchymal to epithelial. Moreover, these events occur repeatedly and periodically. We here overview the inductive events that have recently been shown to play important roles in the formation of the intersomitic fissures. We then discuss molecular mechanisms underlying these inductive actions, and also discuss how the fissure formation is interpreted by the subsequent morphogenesis, including cell epithelialization and the acquisition of anterior-posterior identities in the newly formed somite. Thus, somitogenesis provides a unique model to understand how sequentially occurring processes of morphogenesis are coordinated in a 3-D environment.. |
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Danielle V. Bower, Yuki Sato, Rusty Lansford, Dynamic lineage analysis of embryonic morphogenesis using transgenic quail and 4D multispectral imaging, Genesis, 10.1002/dvg.20754, 2011.07, We describe the development of transgenic quail that express various fluorescent proteins in targeted manners and their use as a model system that integrates advanced imaging approaches with conventional and emerging molecular genetics technologies. We also review the progression and complications of past fate mapping techniques that led us to generate transgenic quail, which permit dynamic imaging of amniote embryogenesis with unprecedented subcellular resolution.. |
| 4. |
Yuki Sato, Dorsal aorta formation
Separate origins, lateral-to-medial migration, and remodeling, Development Growth and Differentiation, 10.1111/dgd.12010, 2013.01, Blood vessel formation is a highly dynamic tissue-remodeling event that can be observed from early development in vertebrate embryos. Dorsal aortae, the first functional intra-embryonic blood vessels, arise as two separate bilateral vessels in the trunk and undergo lateral-to-medial translocation, eventually fusing into a single large vessel at the midline. After this dramatic remodeling, the dorsal aorta generates hematopoietic stem cells. The dorsal aorta is a good model to use to increase our understanding of the mechanisms controlling the establishment and remodeling of larger blood vessels in vivo. Because of the easy accessibility to the developing circulatory system, quail and chick embryos have been widely used for studies on blood vessel formation. In particular, the mapping of endothelial cell origins has been performed using quail-chick chimera analysis, revealing endothelial, vascular smooth muscle, and hematopoietic cell progenitors of the dorsal aorta. The avian embryo model also allows conditional gene activation/inactivation and direct observation of cell behaviors during dorsal aorta formation. This allows a better understanding of the molecular mechanisms underlying specific morphogenetic events during dynamic dorsal aorta formation from a cell behavior perspective.. |
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Yuki Sato, Rusty Lansford, Transgenesis and imaging in birds, and available transgenic reporter lines, Development Growth and Differentiation, 10.1111/dgd.12058, 2013.05, Avian embryos are important model organism to study higher vertebrate development. Easy accessibility to developing avian embryos enables a variety of experimental applications to understand specific functions of molecules, tissue-tissue interactions, and cell lineages. The whole-mount ex ovo culture technique for avian embryos permits time-lapse imaging analysis for a better understanding of cell behaviors underlying tissue morphogenesis in physiological conditions. To study mechanisms of blood vessel formation and remodeling in developing embryos by using a time-lapse imaging approach, a transgenic quail model, Tg(tie1:H2B-eYFP), was generated. From a cell behavior perspective, Tg(tie1:H2B-eYFP) quail embryos are a suitable model to shed light on how the structure and pattern of blood vessels are established in higher vertebrates. In this manuscript, we give an overview on the biological and technological background of the transgenic quail model and describe procedures for the ex ovo culture of quail embryos and time-lapse imaging analysis. Development, Growth & Differentiation. |
