1. Hox-mediated endodermal identity patterns the pharyngeal muscle formation in the chordate pharynx
- Author
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Azusa Nakahata, Takashi Yamamoto, Keita Yoshida, Nicholas Treen, Yasunori Sasakura, and Tetsushi Sakuma
- Subjects
0301 basic medicine ,Mesoderm ,animal structures ,Tretinoin ,Chordate ,Muscle Development ,Pharyngeal muscles ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Animals ,Ciona intestinalis ,Hox gene ,Molecular Biology ,Feedback, Physiological ,Homeodomain Proteins ,biology ,Endoderm ,Anatomy ,biology.organism_classification ,Ciona ,030104 developmental biology ,medicine.anatomical_structure ,embryonic structures ,Pharyngeal Muscles ,Pharynx ,030217 neurology & neurosurgery ,Developmental Biology ,Endostyle - Abstract
The pharynx, possessing gill slits and the endostyle, is a characteristic of chordates that is a complex of multiple tissues well organized along the anterior-posterior (AP) axis. Although Hox genes show AP coordinated expression in the pharyngeal endoderm, tissue specific roles of these factors for establishing the regional identities within this tissue is largely unknown. Here, we show that Hox1 is essential for the establishment of AP axial identity of the endostyle, a major structure of the pharyngeal endoderm, in the ascidian Ciona intestinalis. We found that Hox1 knockout causes posterior to anterior transformation of the endostyle identity, and Hox1 represses Otx expression and anterior identity, and vice versa. Furthermore, alteration of the regional identity of the endostyle disrupts the formation of body wall muscles, suggesting that the endodermal axial identity is essential for the coordinated pharyngeal development. Our results reveal an essential role of Hox genes for establishment of the AP regional identity in the pharyngeal endoderm and crosstalk between endoderm and mesoderm for the development of chordate pharynx.
- Published
- 2017