Physical interaction between Tbx6 and mespb is indispensable for the activation of bowline expression during Xenopus somitogenesis.
During vertebrate somitogenesis, various transcriptional factors function coordinately to determine the position of the somite boundary. Previously, we reported on the signaling crosstalk that occurs between two major transcription factors involved in somitogenesis, Tbx6 and mespb/mesp2. These factors synergistically activated the expression of a downstream gene, bowline/Ripply2, which is essential for precise formation of the somite boundary. However, the molecular mechanism underlying this synergistic effect remains unclear. In this report, we found that the Tbx6 and mespb proteins interacted physically with each other. Pulldown assays with various deletion mutants of these proteins identified the essential domains for this physical interaction. Finally, we found that interference with the physical interaction by a dominant-negative form of mespb, mespbDeltaDBD, abrogated the expression of the bowline gene during Xenopus somitogenesis. These results indicate that the appropriate expression of bowline/Ripply2 is regulated by a direct interaction between the Tbx6 and mespb proteins during Xenopus somitogenesis.
Department of Life Sciences (Biology), Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
Keisuke
K
Hitachi
Hiroki
H
Danno
Akiko
A
Kondow
Kiyoshi
K
Ohnuma
Hideho
H
Uchiyama
Shoichi
S
Ishiura
Akira
A
Kurisaki
Makoto
M
Asashima
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D050436:Regulatory Elements, Transcriptional; D019170:Somites / Q000196:embryology* / Q000378:metabolism; D020825:T-Box Domain Proteins / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics* / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism
D051792:Basic Helix-Loop-Helix Proteins; D020825:T-Box Domain Proteins; D029867:Xenopus Proteins; C530218:Mespb protein, Xenopus; C491181:Tbx6 protein, Xenopus; C512374:ripply2.2 protein, Xenopus