PUBLICATION

Essential and opposing roles of zebrafish β-catenins in the formation of dorsal axial structures and neurectoderm

Authors
Bellipanni, G., Varga, M., Maegawa, S., Imai, Y., Kelly, C., Myers, A.P., Chu, F., Talbot, W.S., and Weinberg, E.S.
ID
ZDB-PUB-060313-12
Date
2006
Source
Development (Cambridge, England)   133(7): 1299-1309 (Journal)
Registered Authors
Bellipanni, Gianfranco, Chu, Felicia, Imai, Yoshiyuki, Kelly, Christina, Maegawa, Shingo, Talbot, William S., Weinberg, Eric
Keywords
β-Catenin, Axis formation, Neural induction, Dorsoventral patterning, Anteroposterior patterning, Organizer, Zebrafish, ctnnb1, ctnnb2
MeSH Terms
  • Amino Acid Sequence
  • Animals
  • Body Patterning/genetics*
  • Chromosome Mapping
  • Chromosomes
  • Computer Simulation
  • Embryo, Nonmammalian
  • Gene Expression Regulation, Developmental
  • Genetic Markers
  • Genome
  • Microinjections
  • Molecular Sequence Data
  • Nervous System/embryology*
  • Oligonucleotides, Antisense/pharmacology
  • Organizers, Embryonic/metabolism
  • Phenotype
  • Phylogeny
  • RNA, Messenger/metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Homology, Amino Acid
  • Zebrafish/embryology*
  • Zebrafish/genetics
  • Zebrafish Proteins*
  • beta Catenin/chemistry
  • beta Catenin/genetics
  • beta Catenin/metabolism*
(all 26)
PubMed
16510506 Full text @ Development
Abstract
In Xenopus, Wnt signals and their transcriptional effector beta-catenin are required for the development of dorsal axial structures. In zebrafish, previous loss-of-function studies have not identified an essential role for beta-catenin in dorsal axis formation, but the maternal-effect mutation ichabod disrupts beta-catenin accumulation in dorsal nuclei and leads to a reduction of dorsoanterior derivatives. We have identified and characterized a second zebrafish beta-catenin gene, beta-catenin-2, located on a different linkage group from the previously studied beta-catenin-1, but situated close to the ichabod mutation on LG19. Although the ichabod mutation does not functionally alter the beta-catenin-2 reading frame, the level of maternal beta-catenin-2, but not beta-catenin-1, transcript is substantially lower in ichabod, compared with wild-type, embryos. Reduction of beta-catenin-2 function in wild-type embryos by injection of morpholino antisense oligonucleotides (MOs) specific for this gene (MO2) results in the same ventralized phenotypes as seen in ichabod embryos, and administration of MO2 to ichabod embryos increases the extent of ventralization. MOs directed against beta-catenin-1 (MO1), by contrast, had no ventralizing effect on wild-type embryos. beta-catenin-2 is thus specifically required for organizer formation and this function is apparently required maternally, because the ichabod mutation causes a reduction in maternal transcription of the gene and a reduced level of beta-catenin-2 protein in the early embryo. A redundant role of beta-catenins in suppressing formation of neurectoderm is revealed when both beta-catenin genes are inhibited. Using a combination of MO1 and MO2 in wild-type embryos, or by injecting solely MO1 in ichabod embryos, we obtain expression of a wide spectrum of neural markers in apparently appropriate anteroposterior pattern. We propose that the early, dorsal-promoting function of beta-catenin-2 is essential to counteract a later, dorsal- and neurectoderm-repressing function that is shared by both beta-catenin genes.
Genes / Markers
Marker Marker Type Name
brsGENEbrass
chrdGENEchordin
ctnnb1GENEcatenin (cadherin-associated protein), beta 1
ctnnb2GENEcatenin, beta 2
dharmaGENEdharma
egr2bGENEearly growth response 2b
emx1GENEempty spiracles homeobox 1
fgf3GENEfibroblast growth factor 3
fgf8aGENEfibroblast growth factor 8a
gscGENEgoosecoid
1 - 10 of 15
Show
Figures
Figure Gallery (5 images)
Show all Figures
Expression
Phenotype
Mutations / Transgenics
Allele Construct Type Affected Genomic Region
b2
    Unknown
    p1
      Unknown
      1 - 2 of 2
      Show
      Human Disease / Model
      No data available
      Sequence Targeting Reagents
      Target Reagent Reagent Type
      ctnnb1MO2-ctnnb1MRPHLNO
      ctnnb1MO3-ctnnb1MRPHLNO
      ctnnb1MO4-ctnnb1MRPHLNO
      ctnnb2MO1-ctnnb2MRPHLNO
      ctnnb2MO2-ctnnb2MRPHLNO
      1 - 5 of 5
      Show
      Fish
      Antibodies
      No data available
      Orthology
      No data available
      Engineered Foreign Genes
      No data available
      Mapping
      Entity Type Entity Symbol Location
      p1Chr: 19 Details
      SSLPz26695Chr: 19 Details
      1 - 2 of 2
      Show