title: Spemann organizer transcriptome induction by early beta-catenin, Wnt, Nodal, and Siamois signals inXenopus laevis.
abstract: The earliest event inXenopusdevelopment is the dorsal accumulation of nuclear β-catenin under the influence of cytoplasmic determinants displaced by fertilization. In this study, a genome-wide approach was used to examine transcription of the 43,673 genes annotated in theXenopus laevisgenome under a variety of conditions that inhibit or promote formation of the Spemann organizer signaling center. Loss of function of β-catenin with antisense morpholinos reproducibly reduced the expression of 247 mRNAs at gastrula stage. Interestingly, only 123 β-catenin targets were enriched on the dorsal side and defined an early dorsal β-catenin gene signature. These genes included several previously unrecognized Spemann organizer components. Surprisingly, only 3 of these 123 genes overlapped with the late Wnt signature recently defined by two other groups using inhibition byDkk1mRNA or Wnt8 morpholinos, which indicates that the effects of β-catenin/Wnt signaling in early development are exquisitely regulated by stage-dependent mechanisms. We analyzed transcriptome responses to a number of treatments in a total of 46 RNA-seq libraries. These treatments included, in addition to β-catenin depletion, regenerating dorsal and ventral half-embryos, lithium chloride treatment, and the overexpression ofWnt8,Siamois, andCerberusmRNAs. Only some of the early dorsal β-catenin signature genes were activated at blastula whereas others required the induction of endomesoderm, as indicated by their inhibition by Cerberus overexpression. These comprehensive data provide a rich resource for analyzing how the dorsal and ventral regions of the embryo communicate with each other in a self-organizing vertebrate model embryo.
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095-1662.|Department of Biological Chemistry, University of California, Los Angeles, CA 90095-1662.
authors.forename: Yi
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095-1662.|Department of Biological Chemistry, University of California, Los Angeles, CA 90095-1662.
authors.forename: Diego
authors.initials: D
authors.lastname: Ploper
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095-1662.|Department of Biological Chemistry, University of California, Los Angeles, CA 90095-1662.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Sosa
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095-1662.|Department of Biological Chemistry, University of California, Los Angeles, CA 90095-1662.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Colozza
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095-1662.|Department of Biological Chemistry, University of California, Los Angeles, CA 90095-1662.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Moriyama
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095-1662.|Department of Biological Chemistry, University of California, Los Angeles, CA 90095-1662.
authors.forename: Maria D J
authors.initials: MD
authors.lastname: Benitez
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095-1662.|Department of Biological Chemistry, University of California, Los Angeles, CA 90095-1662.
authors.forename: Kelvin
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Medicine, University of California, Los Angeles, CA 90095-1662.|Department of Microbiology, University of California, Los Angeles, CA 90095-1662.|Department of Human Genetics, University of California, Los Angeles, CA 90095-1662.
authors.forename: Daria
authors.initials: D
authors.lastname: Merkurjev
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90095-1662; ederobertis@mednet.ucla.edu.|Department of Biological Chemistry, University of California, Los Angeles, CA 90095-1662.
authors.forename: Edward M
authors.initials: EM
authors.lastname: De Robertis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D055457:Nodal Protein / Q000235:genetics / Q000378:metabolism; D020897:Organizers, Embryonic / Q000502:physiology*; D017385:Sequence Homology; D059467:Transcriptome; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
chemical_list: D018398:Homeodomain Proteins; D055457:Nodal Protein; C093133:SIA1 protein, Xenopus; D051153:Wnt Proteins; D029867:Xenopus Proteins; D051176:beta Catenin
keywords: Cerberus; Spemann organizer; Wnt signaling; embryonic induction; embryonic patterning