title: Hox-mediated endodermal identity patterns pharyngeal muscle formation in the chordate pharynx.
abstract: The chordate pharynx, possessing gill slits and the endostyle, is a complex of multiple tissues that are highly 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 have not been demonstrated. Here, we show thatHox1is essential for the establishment of AP axial identity of the endostyle, a major structure of the pharyngeal endoderm, in the ascidianCiona intestinalisWe found that knockout ofHox1causes posterior-to-anterior transformation of the endostyle identity, and thatHox1repressesOtxexpression 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 coordinated pharyngeal development. Our results demonstrate an essential role of Hox genes in establishment of the AP regional identity in the pharyngeal endoderm and reveal crosstalk between endoderm and mesoderm during development of chordate pharynx.
authors.affiliation: Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan kyoshida@shimoda.tsukuba.ac.jp.
authors.forename: Keita
authors.identifier: 0000-0001-5557-9214
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan.
authors.forename: Azusa
authors.initials: A
authors.lastname: Nakahata
authors.affiliation: Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Treen
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Sakuma
authors.affiliation: Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Sasakura
mesh_terms: D000818:Animals; D002938:Ciona intestinalis; D004707:Endoderm / Q000187:drug effects / Q000196:embryology*; D025461:Feedback, Physiological / Q000187:drug effects; D018398:Homeodomain Proteins / Q000378:metabolism*; D024510:Muscle Development / Q000187:drug effects; D010609:Pharyngeal Muscles / Q000187:drug effects / Q000196:embryology*; D010614:Pharynx / Q000187:drug effects / Q000196:embryology*; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D018398:Homeodomain Proteins; D014212:Tretinoin
keywords: Ascidian; Ciona; Endoderm; Hox; Pharyngeal muscle; Pharynx