Mindin/F-spondin family: novel ECM proteins expressed in the zebrafish embryonic axis

Higashijima, S., Nose, A., Eguchi, G., Hotta, Y., and Okamoto, H.
Developmental Biology   192: 211-227 (Journal)
Registered Authors
Higashijima, Shin-ichi, Okamoto, Hitoshi
MeSH Terms
  • Amino Acid Sequence
  • Animals
  • Consensus Sequence
  • Drosophila Proteins
  • Drosophila melanogaster/embryology
  • Drosophila melanogaster/genetics
  • Embryo, Nonmammalian/physiology
  • Extracellular Matrix Proteins/biosynthesis
  • Extracellular Matrix Proteins/genetics
  • Extracellular Matrix Proteins/physiology*
  • Gene Expression Regulation, Developmental*
  • Growth Substances*
  • Molecular Sequence Data
  • Multigene Family
  • Neural Cell Adhesion Molecules/physiology*
  • Peptides*
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Zebrafish/embryology*
  • Zebrafish Proteins*
9441663 Full text @ Dev. Biol.
F-spondin is a secreted protein expressed at high levels by the floor plate cells. The C-terminal half of the protein contains six thrombospondin type 1 repeats, while the N-terminal half exhibited virtually no similarity to any other protein until recently, when a Drosophila gene termed M-spondin was cloned; its product was found to share two conserved domains with the N-terminal half of F-spondin. We report the molecular cloning of four zebrafish genes encoding secreted proteins with these conserved domains. Two are zebrafish homologs of F-spondin, while the other two, termed mindin1 and mindin2, encode mutually related novel proteins, which are more related to the Drosophila M-spondin than to F-spondin. During embryonic development, all four genes are expressed in the floor plate cells. In addition to the floor plate, mindin1 is expressed in the hypochord cells, while mindin2 is expressed in the sclerotome cells. When ectopically expressed, Mindin proteins selectively accumulate in the basal lamina, suggesting that Mindins are extracellular matrix (ECM) proteins with high affinity to the basal lamina. We also report the spatial distribution of one of the F-spondin proteins, F-spondin2. F-spondin2 is localized to the thread-like structure in the central canal of the spinal cord, which is likely to correspond to Reissner's fiber known to be present in the vertebrate phylum. In summary, our study has defined a novel gene family of ECM molecules in the vertebrate, all of which may potentially be involved in development of the midline structure.
Genes / Markers
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Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes