title: Formation of a "Pre-mouth Array" from the Extreme Anterior Domain Is Directed by Neural Crest and Wnt/PCP Signaling.
abstract: The mouth arises from the extreme anterior domain (EAD), a region where the ectoderm and endoderm are directly juxtaposed. Here, we identify a "pre-mouth array" in Xenopus that forms soon after the cranial neural crest has migrated to lie on either side of the EAD. Initially, EAD ectoderm comprises a wide and short epithelial mass that becomes narrow and tall with cells and nuclei changing shape, a characteristic of convergent extension. The resulting two rows of cells-the pre-mouth array-later split down the midline to surround the mouth opening. Neural crest is essential for convergent extension and likely signals to the EAD through the Wnt/planar cell polarity (PCP) pathway. Fzl7 receptor is locally required in EAD ectoderm, while Wnt11 ligand is required more globally. Indeed, heterologous cells expressing Wnt11 can elicit EAD convergent extension. The study reveals a precise cellular mechanism that positions and contributes to the future mouth.
authors.affiliation: Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA; Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Harvard School of Dental Medicine, 188 Longwood Avenue, Boston, MA 02115, USA; Harvard-MIT Health Sciences and Technology Program, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA; Biological Sciences in Dental Medicine Program, Harvard Graduate School of Arts and Sciences, 1350 Massachusetts Avenue, Holyoke Center 350, Cambridge, MA 02138, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Jacox
authors.affiliation: Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA; Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Chen
authors.affiliation: Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA; Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Rothman
authors.affiliation: Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA; Harvard School of Dental Medicine, 188 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Hillary
authors.initials: H
authors.lastname: Lathrop-Marshall
authors.affiliation: Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA; Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA. Electronic address: sive@wi.mit.edu.
authors.forename: Hazel
authors.initials: H
authors.lastname: Sive
mesh_terms: D000818:Animals; D016764:Cell Polarity / Q000502:physiology*; D004475:Ectoderm / Q000378:metabolism; D004707:Endoderm / Q000378:metabolism; D009055:Mouth / Q000378:metabolism*; D009432:Neural Crest / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D051153:Wnt Proteins / Q000378:metabolism*; D029867:Xenopus Proteins / Q000378:metabolism; D014982:Xenopus laevis / Q000378:metabolism
chemical_list: D051153:Wnt Proteins; D029867:Xenopus Proteins