PUBLICATION

misty somites, a maternal effect gene identified by transposon-mediated insertional mutagenesis in zebrafish that is essential for the somite boundary maintenance

Authors
Kotani, T., and Kawakami, K.
ID
ZDB-PUB-080326-20
Date
2008
Source
Developmental Biology   316(2): 383-396 (Journal)
Registered Authors
Kawakami, Koichi
Keywords
Zebrafish, Transposon-mediated gene trapping, Maternal effect mutants, Somitogenesis, Epithlialization of somitic cells, Lamellipodia formation
MeSH Terms
  • DNA Transposable Elements*
  • In Situ Hybridization
  • Embryo, Nonmammalian/physiology
  • DNA Primers
  • Animals
  • Female
  • Zebrafish/embryology*
  • Zebrafish/genetics*
  • Animals, Genetically Modified
  • Polymerase Chain Reaction
  • Zebrafish Proteins/genetics*
  • Mutagenesis, Insertional*
(all 12)
PubMed
18342848 Full text @ Dev. Biol.
Abstract
Somite boundary formation is crucial for segmentation of vertebrate somites and vertebrae and skeletal muscle morphogenesis. Previously, we developed a Tol2 transposon-mediated gene trap method in zebrafish. In the present study, we aimed to isolate transposon insertions that trap maternally-expressed genes. We found that homozygous female fish carrying a transposon insertion within a maternally-expressed gene misty somites (mys) produced embryos that showed obscure somite boundaries at the early segmentation stage (12-13 hpf). The somite boundaries became clear and distinct after this period and the embryos survived to adulthood. This phenotype was rescued by expression of mys cDNA in the homozygous adults, confirming that it was caused by a decreased mys activity. We analyzed a role of the mys gene by using morpholino oligonucleotides (MOs). The MO-injected embryo exhibited severer phenotypes than the insertional mutant probably because the mys gene was partially active in the insertional mutant. The MO-injected embryo also showed the obscure somite boundary phenotype. Fibronectin and phosphorylated FAK at the intersomitic regions were accumulated at the boundaries at this stage, but, unlike wild type embryos, somitic cells adjacent to the boundaries did not undergo epithelialization, suggesting that Mys is required for epithelialization of the somitic cells. Then in the MO-injected embryos, the boundaries once became clear and distinct, but, in the subsequent stages, disappeared, resulting in abnormal muscle morphogenesis. Accumulation of Fibronectin and phosphorylated FAK observed in the initial stage also disappeared. Thus, Mys is crucial for maintenance of the somite boundaries formed at the initial stage. To analyze the mys defect at the cellular level, we placed cells dissociated from the MO-injected embryo on Fibronectin-coated glasses. By this cell spreading assay, we found that the mys-deficient cells reduced the activity to form lamellipodia on F. To analyze the mys defect at the cellular level, we placed cells dissociated from the MO-injected embryo on Fibronectin-coated glasses. By this cell spreading asibronectin while FAK was activated in these cells. Thus, we demonstrate that a novel gene misty somites is essential for epithelialization of the somitic cells and maintenance of the somite boundary. Furthermore, Mys may play a role in a cellular pathway leading to lamellipodia formation in response to the Fibronectin signaling. We propose that the Tol2 transposon mediated gene trap method is powerful to identify a novel gene involved in vertebrate development.
Genes / Markers
Figures
Figure Gallery (9 images)
Show all Figures
Expression
Phenotype
Mutations / Transgenics
Allele Construct Type Affected Genomic Region
nk001tkTgTransgenic Insertion
    nksag014GtTransgenic Insertion
      nksag020GtTransgenic Insertion
      nksag086GtTransgenic Insertion
        nksagm011aGtTransgenic Insertion
        nksagm011bGtTransgenic Insertion
          nksagm011cGtTransgenic Insertion
            nksagm011dGtTransgenic Insertion
              nksagm011eGtTransgenic Insertion
              nksagm018bGtTransgenic Insertion
              1 - 10 of 17
              Show
              Human Disease / Model
              No data available
              Sequence Targeting Reagents
              Target Reagent Reagent Type
              prrc1MO1-prrc1MRPHLNO
              prrc1MO2-prrc1MRPHLNO
              prrc1MO3-prrc1MRPHLNO
              1 - 3 of 3
              Show
              Fish
              Antibodies
              No data available
              Orthology
              Gene Orthology
              prrc1
              1 - 1 of 1
              Show
              Engineered Foreign Genes
              Marker Marker Type Name
              GFPEFGGFP
              1 - 1 of 1
              Show
              Mapping
              No data available