title: Differential diffusivity of Nodal and Lefty underlies a reaction-diffusion patterning system.
abstract: Biological systems involving short-range activators and long-range inhibitors can generate complex patterns. Reaction-diffusion models postulate that differences in signaling range are caused by differential diffusivity of inhibitor and activator. Other models suggest that differential clearance underlies different signaling ranges. To test these models, we measured the biophysical properties of the Nodal/Lefty activator/inhibitor system during zebrafish embryogenesis. Analysis of Nodal and Lefty gradients revealed that Nodals have a shorter range than Lefty proteins. Pulse-labeling analysis indicated that Nodals and Leftys have similar clearance kinetics, whereas fluorescence recovery assays revealed that Leftys have a higher effective diffusion coefficient than Nodals. These results indicate that differential diffusivity is the major determinant of the differences in Nodal/Lefty range and provide biophysical support for reaction-diffusion models of activator/inhibitor-mediated patterning.
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA. pmueller@fas.harvard.edu
authors.forename: Patrick
authors.initials: P
authors.lastname: Müller
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Rogers
authors.forename: Ben M
authors.initials: BM
authors.lastname: Jordan
authors.forename: Joon S
authors.initials: JS
authors.lastname: Lee
authors.forename: Drew
authors.initials: D
authors.lastname: Robson
authors.forename: Sharad
authors.initials: S
authors.lastname: Ramanathan
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Schier
mesh_terms: D000818:Animals; D036703:Blastula / Q000378:metabolism*; D019521:Body Patterning; D004058:Diffusion; D047108:Embryonic Development; D036681:Fluorescence Recovery After Photobleaching; D006207:Half-Life; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D055458:Left-Right Determination Factors / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D055456:Nodal Signaling Ligands / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D055458:Left-Right Determination Factors; C572343:Lft2 protein, zebrafish; D055456:Nodal Signaling Ligands; D011993:Recombinant Fusion Proteins; D029961:Zebrafish Proteins; C117508:lft1 protein, zebrafish; C485171:ndr1 protein, zebrafish; C512832:ndr2 protein, zebrafish