title: Scaling of dorsal-ventral patterning in the Xenopus laevis embryo.
abstract: Scaling of pattern with size has been described and studied for over a century, yet its molecular basis is understood in only a few cases. In a recent, elegant study, Inomata and colleagues proposed a new model explaining how bone morphogenic protein (BMP) activity gradient scales with embryo size in the early Xenopus laevis embryo. We discuss their results in conjunction with an alternative model we proposed previously. The expansion-repression mechanism (ExR) provides a conceptual framework unifying both mechanisms. Results of Inomata and colleagues implicate the chordin-stabilizing protein sizzled as the expander molecule enabling scaling, while we attributed this role to the BMP ligand Admp. The two expanders may work in concert, as suggested by the mathematical model of Inomata et al. We discuss approaches for differentiating the contribution of sizzled and Admp to pattern scaling.
authors: Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA.
authors: Danny
authors: D
authors: Ben-Zvi
authors: Abraham
authors: A
authors: Fainsod
authors: Ben-Zion
authors: BZ
authors: Shilo
authors: Naama
authors: N
authors: Barkai
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000196:embryology* / Q000378:metabolism; D008962:Models, Theoretical; D014982:Xenopus laevis / Q000196:embryology* / Q000378:metabolism
chemical_list: D019485:Bone Morphogenetic Proteins
keywords: BMP; Xenopus; development; mathematical modeling; morphogen gradient; patterning; scaling