Essential Role of the Transcription Factor Ets-2 in
Xenopus Early Development*
Kaoru
Kawachi,
Norihisa
Masuyama, and
Eisuke
Nishida
From the Department of Cell and Developmental Biology, Graduate
School of Biostudies, Kyoto University, Sakyo-ku,
Kyoto 606-8502, Japan
The fibroblast growth factor (FGF)/MAPK pathway
plays an important role in early Xenopus developmental
processes, including mesoderm patterning. The activation of the MAPK
pathway leads to induction of Xenopus Brachyury (Xbra),
which regulates the transcription of downstream mesoderm-specific genes
in mesoderm patterning. However, the link between the FGF/MAPK pathway
and the induction of Xbra has not been fully understood. Here we
present evidence suggesting that Ets-2 is involved in the induction of Xbra and thus in the development of posterior mesoderm during early
embryonic development. Overexpression of Ets-2 caused posteriorized embryos and led to the induction of mesoderm in ectodermal explants. Expression of a dominant-negative form of Ets-2 or injection of antisense morpholino oligonucleotides against Ets-2 inhibited the
formation of the trunk and tail structures. Overexpression of Ets-2
resulted in the induction of Xbra, and expression of the
dominant-negative Ets-2 inhibited FGF- or constitutively active MEK-induced Xbra expression. Moreover, overexpression of Ets-2 up-regulated the transcription from Xbra promoter reporter gene constructs. Ets-2 bound to the Xbra promoter region in
vitro. These results taken together indicate that
Xenopus Ets-2 plays an essential role in mesoderm
patterning, lying between the FGF/MAPK pathway and the Xbra transcription.
*
This work was supported by grants from the Ministry of
Education, Science and Culture of Japan (to E. N.).The costs of publication of this
article were defrayed in part by the
payment of page charges. The article
must therefore be hereby marked
"advertisement" in accordance with 18 U.S.C. Section
1734 solely to indicate this fact.