Transcription factor Tbx6 plays a central role in fate determination between mesenchyme and muscle in embryos of the ascidian, Halocynthia roretzi.
Developmental fates are determined in relation to other fates in surrounding cells within the embryo, creating diversified tissue or cell types in the course of development. In ascidian embryos, maternally localized factors and inductive signals play essential and cooperative roles in fate determination at appropriate spatial and temporal positions during embryogenesis. Here, to clarify fate determination mechanisms of mesenchyme and muscle during mesenchyme induction by the fibroblast growth factor (FGF) signal in Halocynthia roretzi, we examined the function of transcription factor Tbx6, which acts as a pivotal mediator of the maternally localized muscle differentiation determinant Macho-1. Our results suggest that the level of Tbx6 expression increases in muscle lineage cells through positive feedback regulation that promotes muscle differentiation as well as mesenchymal fate suppression. In addition, the FGF signal inactivated Tbx6 transcriptional activity and positive feedback, leading to induction of the mesenchymal lineage. Taken together, our finding suggests that Tbx6 is an important factor for determining mesenchyme and muscle fates.
Asamushi Research Center for Marine Biology, Graduate School of Life Science, Tohoku University, 9 Sakamoto, Asamushi, Aomori, 039-3501, Japan.
Gaku
G
Kumano
Nobue
N
Negoro
Hiroki
H
Nishida
D000818:Animals; D002070:Butadienes / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D019070:Cell Lineage; D008648:Mesoderm / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D008969:Molecular Sequence Data; D009132:Muscles / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D020825:T-Box Domain Proteins / Q000378:metabolism*; D014561:Urochordata / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism*
D002070:Butadienes; D009570:Nitriles; D020825:T-Box Domain Proteins; C113580:U 0126
Tbx6; ascidian; induction; mesenchyme; muscle