ZFIN ID: ZDB-PUB-050523-8
Otolith matrix proteins OMP-1 and Otolin-1 are necessary for normal otolith growth and their correct anchoring onto the sensory maculae
Murayama, E., Herbomel, P., Kawakami, A., Takeda, H., and Nagasawa H.
Date: 2005
Source: Mechanisms of Development   122(6): 791-803 (Journal)
Registered Authors: Herbomel, Philippe, Kawakami, Atsushi, Murayama, Emi, Takeda, Hiroyuki
Keywords: Biomineralization; Matrix protein; Morpholino; Otolith; Zebrafish
MeSH Terms:
  • Amino Acid Sequence
  • Animals
  • Calcium Carbonate/metabolism
  • Cloning, Molecular
  • DNA, Complementary/metabolism
  • Ear, Inner/embryology
  • Extracellular Matrix Proteins/physiology*
  • Gene Expression Regulation, Developmental*
  • In Situ Hybridization
  • Microscopy, Video
  • Molecular Sequence Data
  • Nerve Tissue Proteins/physiology*
  • Olfactory Marker Protein
  • Oligonucleotides, Antisense/pharmacology
  • Otolithic Membrane/embryology*
  • Otolithic Membrane/physiology
  • Phalloidine/pharmacology
  • Phenotype
  • Protein Structure, Tertiary
  • RNA, Messenger/metabolism
  • Time Factors
  • Zebrafish
  • Zebrafish Proteins
PubMed: 15905077 Full text @ Mech. Dev.
FIGURES
ABSTRACT
Fish otoliths are highly calcified concretions deposited in the inner ear and serve as a part of the hearing and balance systems. They consist mainly of calcium carbonate and a small amount of organic matrix. The latter component is considered to play important roles in otolith formation. Previously, we identified two major otolith matrix proteins, OMP-1 (otolith matrix protein-1) and Otolin-1, from salmonid species. To assess the function of these proteins in otolith formation, we performed antisense morpholino oligonucleotide (MO)-mediated knockdown of omp-1 and otolin-1 in zebrafish embryos. We first identified zebrafish cDNA homologs of omp-1 (zomp-1) and otolin-1 (zotolin-1). Whole-mount in situ hybridization then revealed that the expression of both zomp-1 and zotolin-1 mRNAs is restricted to the otic vesicles. zomp-1 mRNA was expressed from the 14-somite stage in the otic placode, but the zOMP-1 protein was detected only from 26-somite stage onwards. In contrast, zotolin-1 mRNA expression became clear around 72hpf. MOs designed to inhibit zomp-1 and zotolin-1 mRNA translation, respectively, were injected into 1-2 cell stage embryos. zomp-1 MO caused a reduction in otolith size and an absence of zOtolin-1 deposition, while zotolin-1 MO caused a fusion of the two otoliths, and an increased instability of otoliths after fixation. We conclude that zOMP-1 is required for normal otolith growth and deposition of zOtolin-1 in the otolith, while zOtolin-1, a collagenous protein, is involved in the correct arrangement of the otoliths onto the sensory epithelium of the inner ear and probably in stabilization of the otolith matrix.
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