title: Specific induction of cranial placode cells from Xenopus ectoderm by modulating the levels of BMP, Wnt, and FGF signaling.
abstract: The neural-epidermal boundary tissues include the neural crest and preplacodal ectoderm (PPE) as primordial constituents. The PPE region is essential for the development of various sensory and endocrine organs, such as the anterior lobe of the pituitary, olfactory epithelium, lens, trigeminal ganglion, and otic vesicles. During gastrulation, a neural region is induced in ectodermal cells that interacts with mesendodermal tissue and responds to several secreted factors. Among them, inhibition of bone morphogenetic protein (BMP) in the presumptive neuroectoderm is essential for the induction of neural regions, and formation of a Wnt and fibroblast growth factor (FGF) signaling gradient along the midline determines anterior-posterior patterning. In this study, we attempted to specifically induce PPE cells from undifferentiated Xenopus cells by regulating BMP, Wnt, and FGF signaling. We showed that the proper level of BMP inhibition with an injection of truncated BMP receptor or treatment with a chemical antagonist triggered the expression of PPE genes. In addition, by varying the amount of injected chordin, we optimized specific expression of the PPE genes. PPE gene expression is increased by adding an appropriate dose of an FGF receptor antagonist. Furthermore, co-injection with either wnt8 or the Wnt inhibitor dkk-1 altered the expression levels of several region-specific genes according to the injected dose. We specifically induced PPE cell differentiation in animal cap cells from early-stage Xenopus embryos by modulating BMP, Wnt, and FGF signaling. This is not the first research on placode induction, but our simple method could potentially be applied to mammalian stem cell systems.
authors.affiliation: Department of Life Sciences (Biology), Graduate School of Arts and Sciences, the University of Tokyo, Tokyo, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Life Sciences (Biology), Graduate School of Arts and Sciences, the University of Tokyo, Tokyo, Japan.
authors.forename: Yuna
authors.initials: Y
authors.lastname: Kanai
authors.affiliation: Department of Life Sciences (Biology), Graduate School of Arts and Sciences, the University of Tokyo, Tokyo, Japan.|RIKEN Center for Developmental Biology, Kobe, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsukawa
authors.affiliation: Department of Life Sciences (Biology), Graduate School of Arts and Sciences, the University of Tokyo, Tokyo, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Michiue
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics; D019485:Bone Morphogenetic Proteins / Q000235:genetics*; D004475:Ectoderm / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D005346:Fibroblast Growth Factors / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006023:Glycoproteins / Q000235:genetics; D006257:Head / Q000196:embryology; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D008845:Microinjections; D009432:Neural Crest / Q000196:embryology / Q000378:metabolism; D054258:Neural Plate / Q000196:embryology / Q000378:metabolism; D010957:Plasmids / Q000008:administration & dosage / Q000235:genetics; D011720:Pyrazoles / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012886:Skull / Q000166:cytology / Q000196:embryology; D051153:Wnt Proteins / Q000235:genetics*; D029867:Xenopus Proteins / Q000235:genetics; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics*
chemical_list: D019485:Bone Morphogenetic Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; C554430:LDN 193189; D011720:Pyrazoles; D011743:Pyrimidines; D011758:Pyrroles; C105686:SU 5402; D051153:Wnt Proteins; D029867:Xenopus Proteins; D005346:Fibroblast Growth Factors; C054234:chordin
keywords: BMP; FGF; Wnt; Xenopus; cranial placode; patterning; prepracodal ectoderm