Percorrer por autor "Shiratori, Hidetaka"
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- Cilia at the node of mouse embryos sense fluid flow for left-right determination via Pkd2Publication . Yoshiba, Satoko; Shiratori, Hidetaka; Kuo, Ivana Y.; Kawasumi, Aiko; Shinohara, Kyosuke; Nonaka, Shigenori; Asai, Yasuko; Sasaki, Genta; Belo, José A.; Sasaki, Hiroshi; Nakai, Junichi; Dworniczak, Bernd; Ehrlich, Barbara E.; Pennekamp, Petra; Hamada, HiroshiUnidirectional fluid flow plays an essential role in the breaking of left-right (L-R) symmetry in mouse embryos, but it has remained unclear how the flow is sensed by the embryo. We report that the Ca2+ channel Polycystin-2 (Pkd2) is required specifically in the perinodal crown cells for sensing the nodal flow. Examination of mutant forms of Pkd2 shows that the ciliary localization of Pkd2 is essential for correct L-R patterning. Whereas Kif3a mutant embryos, which lack all cilia, failed to respond to an artificial flow, restoration of primary cilia in crown cells rescued the response to the flow. Our results thus suggest that nodal flow is sensed in a manner dependent on Pkd2 by the cilia of crown cells located at the edge of the node.
- Left-right asymmetry in the level of active Nodal protein produced in the node is translated into left-right asymmetry in the lateral plate of mouse embryosPublication . Kawasumi, Aiko; Nakamura, Tetsuya; Iwai, Naomi; Yashiro, Kenta; Saijoh, Yukio; Belo, Jose Antonio; Shiratori, Hidetaka; Hamada, HiroshiLeft-right (L-R) asymmetry in the mouse embryo is generated in the node and is dependent on cilia-driven fluid flow, but how the initial asymmetry is transmitted from the node to the lateral plate has remained unknown. We have now identified a transcriptional enhancer (ANE) in the human LEFTY1 gene that exhibits marked L>R asymmetric activity in perinodal cells of the mouse embryo. Dissection of ANE revealed that it is activated in the perinodal cells on the left side by Nodal signaling, suggesting that Nodal activity in the node is asymmetric at a time when Nodal expression is symmetric. Phosphorylated Smad2/3 (pSmad2) indeed manifested an L-R asymmetric distribution at the node, being detected in perinodal cells preferentially on the left side. This asymmetry in pSmad2 distribution was found to be generated not by unidirectional transport of Nodal but rather as a result of LR distribution of active Nodal in the node is translated into the asymmetry in LPM. (C) 2011 Elsevier Inc. All rights reserved.
- Mechanisms of left-right asymmetric signal generation around the nodePublication . Kawasumi, Aiko; Iwai, Naomi; Belo, José A.; Nakamura, Tetsuya; Shiratori, Hidetaka; Hamada, Hiroshi