In Xenopus, multiple nodal-related genes are expressed during early embryogenesis. Among them, only Xenopus nodal related-1(Xnr-1) is expressed unilaterally in the left lateral plate mesoderm(LPM) at the late neurula-early tailbud stage. Early studies report that ectopic administration of Xnr-1 in the right hemisphere at the cleavage stage alters the left-right specification of the heart and visceral organs, or else makes a secondary axis. However, because Xnr-1 and other Xnrs function already at the blastula-gastrula stage, it is very difficult to evaluate the correct timing of the effects of excessively administered Xnr-1 from such a method. To elucidate the essential role of Xnr-1 within the left LPM, ectopic potentiation of Nodal signaling in the right lateral plate mesoderm was performed. Right-side injection of Nodal protein changed the laterality of Xnr-1 and Xenopuspitx2, but lefty, and fully (more than 90%) reversed the situs of the internal organs. Polyethyleneimine-based gene transfer of Xnr-1 mRNA in the right LPM also changed the laterality of pitx2 and fully (more than 90%) reversed the situs of the internal organs. Taken together, the potentiation of Xnr-1 signaling in the right LPM induces pitx2 in the right side and fully inverts the left-right axis of the heart and visceral organs, suggesting that the right LPM can transduce Nodal signaling, and only the absence of the Xnr-1 ligand silences the Nodal signaling in the right LPM. Normal left-right balance of Xnr-1 signaling is needed for the normal left-right specification of the internal organs.
雑誌名
Science Journal of Kanagawa University
巻
16
ページ
35 - 44
発行年
2005-05-25
ISSN
1880-0483
書誌レコードID
AA12068302
著者版フラグ
publisher
その他の言語のタイトル
The potentiation of Nodal signaling in the right lateral plate mesoderm inverts the left-right specification of the internal organs.
アフリカツメガエル胚右側板中胚葉におけるNodalシグナリングの活性化は内臓左右軸を逆転する(2003-2004年度神奈川大学共同研究奨励助成論文)
SJKU Vol 16 2005 35-44.pdf
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