mNanog possesses dorsal mesoderm-inducing ability by modulating both BMP and Activin/nodal signaling in Xenopus ectodermal cells.
BACKGROUND
In Xenopus early embryogenesis, various genes are involved with mesoderm formation. In particular, dorsal mesoderm contains the organizer region and induces neural tissues through the inhibition of bone morphogenetic protein (BMP) signaling. In our initial study to identify novel genes necessary for maintaining the undifferentiated state, we unexpectedly revealed mesoderm-inducing activity for mNanog in Xenopus.


RESULTS
The present series of experiments investigated the effect of mNanog gene expression on Xenopus embryo. Ectopic expression of mNanog induced dorsal mesoderm gene activity, secondary axis formation, and weakly upregulated Activin/nodal signaling. The injection of mNanog also effectively inhibited the target genes of BMP signaling, while Xvent2 injection downregulated the dorsal mesoderm gene expression induced by mNanog injection.


CONCLUSIONS
These results suggested that mNanog expression induces dorsal mesoderm by regulating both Activin/nodal signaling and BMP signaling in Xenopus. This finding highlights the possibly novel function for mNanog in stimulating the endogenous gene network in Xenopus mesoderm formation.
Department of Life Sciences (Biology), Graduate School of Arts and Sciences, the University of Tokyo, Tokyo, Japan.
Aya
A
Miyazaki
Kentaro
K
Ishii
Satoshi
S
Yamashita
Susumu
S
Nejigane
Shinya
S
Matsukawa
Yuzuru
Y
Ito
Yasuko
Y
Onuma
Makoto
M
Asashima
Tatsuo
T
Michiue
D028341:Activins / Q000378:metabolism*; D000818:Animals; D036703:Blastula / Q000166:cytology; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D004475:Ectoderm / Q000166:cytology* / Q000378:metabolism; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008648:Mesoderm / Q000378:metabolism; D000071317:Nanog Homeobox Protein; D055457:Nodal Protein / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014981:Xenopus / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*
D019485:Bone Morphogenetic Proteins; D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D055457:Nodal Protein; D014157:Transcription Factors; D029867:Xenopus Proteins; C099992:ventx2.1 protein, Xenopus; D028341:Activins