title: Differential requirement of bone morphogenetic protein receptors Ia (ALK3) and Ib (ALK6) in early embryonic patterning and neural crest development.
abstract: BACKGROUND
  Bone morphogenetic proteins regulate multiple processes in embryonic development, including early dorso-ventral patterning and neural crest development. BMPs activate heteromeric receptor complexes consisting of type I and type II receptor-serine/threonine kinases. BMP receptors Ia and Ib, also known as ALK3 and ALK6 respectively, are the most common type I receptors that likely mediate most BMP signaling events. Since early expression patterns and functions in Xenopus laevis development have not been described, we have addressed these questions in the present study.
  
  
  RESULTS
  Here we have analyzed the temporal and spatial expression patterns of ALK3 and ALK6; we have also carried out loss-of-function studies to define the function of these receptors in early Xenopus development. We detected both redundant and non-redundant roles of ALK3 and ALK6 in dorso-ventral patterning. From late gastrula stages onwards, their expression patterns diverged, which correlated with a specific, non-redundant requirement of ALK6 in post-gastrula neural crest cells. ALK6 was essential for induction of neural crest cell fate and further development of the neural crest and its derivatives.
  
  
  CONCLUSIONS
  ALK3 and ALK6 both contribute to the gene regulatory network that regulates dorso-ventral patterning; they play partially overlapping and partially non-redundant roles in this process. ALK3 and ALK6 are independently required for the spatially restricted activation of BMP signaling and msx2 upregulation at the neural plate border, whereas in post-gastrula development ALK6 exerts a highly specific, conserved function in neural crest development.
authors.affiliation: Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058, Erlangen, Germany. carolin.schille@fau.de.
authors.forename: Carolin
authors.initials: C
authors.lastname: Schille
authors.affiliation: Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058, Erlangen, Germany. jens.heller@uk-erlangen.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Heller
authors.affiliation: Biology Department, Developmental Biology, Friedrich-Alexander University Erlangen-Nuremberg, 91058, Erlangen, Germany. alexandra.schambony@fau.de.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Schambony
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000235:genetics / Q000378:metabolism*; D052006:Bone Morphogenetic Protein Receptors, Type II / Q000235:genetics / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D009432:Neural Crest / Q000196:embryology* / Q000378:metabolism; D010641:Phenotype; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics
chemical_list: D029867:Xenopus Proteins; C000611684:bmpr1a protein, Xenopus; C000611685:bmpr1b protein, Xenopus; D052005:Bone Morphogenetic Protein Receptors, Type I; D052006:Bone Morphogenetic Protein Receptors, Type II