アクティブボード・２０１０年８月
　　　　　・・・・・２０１０年　８月　２日更新・・・・・

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；Sall4 is a crucial transcriptional regulator for mouse primordial germ cell specification.
　
発表者；　山口　泰華　氏
　　　（熊本大学　発生医学研究所　腎臓発生分野）

Abstract；
Specification of mouse germ-cell lineage commences with the repression of a genetic activity for somatic differentiation and the re-activation of one for stem-cell maintenance in the precursors of the primordial germ cells (PGCs), but precise mechanisms of the regulation of these genetic programs is poorly understood. In the present study, we found that spalt-like 4 protein (Sall4), a Zn-finger nuclear protein, which is expressed predominantly in PGCs, plays crucial roles in the somatic program repression in PGC specification. By analyzing Sall4 conditional knockout mice in germ cells, we found that Sall4-null PGCs were absent from the embryonic gonad, due to the transition defect from the mesoderm to the endoderm just behind the PGC specification. By examining the expression of genes for both somatic and stem-cell programs in Sall4-null PGCs, we found that Sall4 contributed to the repression of the somatic gene activity (Hoxb1), but not to the reactivation of the stem-cell gene activity, during the PGC specification. Then, such Sall4-null PGCs failed to transit and were eliminated by apoptotic cell death. These findings therefore strongly suggested that Sall4 plays important roles in the PGC specification by the repression of the gene activity for somatic differentiation, which is an essential step for the establishment of germ cell population in the embryonic gonad.