アクティブボード・２０１０年８月
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研究発表を行った学会；
・第４３回日本発生生物学会年会.
　２０１０年　６月２０日〜２３日（京都）

タイトル；Dullard is required for mouse primordial germ cell formation by coordinating canonical Wnt signalling in the embryo.
　
発表者；　田中　聡　氏
　　　（熊本大学　発生医学研究所　腎臓発生分野）

Abstract；
Mouse primordial germ cell (PGC) formation is known to be coordinated by BMP signalling activity. In this study, however, we demonstrated that Dullard, a serine/threonine phosphatase is required for the PGC formation independently of BMP4 activity or genetic interaction between Bmp4 and Dullard. In the Dullard-/- embryo, PGCs are absent due to the impaired recruitment of precursors to the germ-line. This is accompanied by the failure of activation of Prdm1 and the abnormal expression pattern of WNT ligands and inhibitors that result in an overall reduction of canonical WNT signalling activity, as revealed by the reduction of b-catenin activity. Consistent with this finding, complete loss of Wnt3 function or partial loss of both Wnt3 and Dullard activity results in the absence of PGCs. In the embryoid body culture of Dullard-/- ES cells, wildtype Dullard, but not mutated Dullard lacking phosphatase activity restored the expression of Prdm1 and germ-line-specific ddx4, suggesting that its phosphatase activity is essential for the germ cell formation. Our results strongly suggested that Dullard is essential for the regulation of canonical WNT signalling activity, which plays a crucial role in the specification of the PGC progenitors.