PUBLICATION

Identification of an osteocalcin isoform in fish with a large acidic prodomain

Authors
Laize, V., Viegas, C.S., Price, P.A., and Cancela, M.L.
ID
ZDB-PUB-060403-3
Date
2006
Source
The Journal of biological chemistry   281(22): 15037-15043 (Journal)
Registered Authors
Keywords
none
MeSH Terms
  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • DNA, Complementary/genetics
  • Evolution, Molecular
  • Hydrogen-Ion Concentration
  • Molecular Sequence Data
  • Osteocalcin/chemistry*
  • Osteocalcin/genetics*
  • Osteocalcin/metabolism
  • Phylogeny
  • Protein Isoforms/chemistry
  • Protein Isoforms/genetics
  • Protein Isoforms/metabolism
  • Protein Structure, Tertiary
  • Takifugu/genetics
  • Tetraodontiformes/genetics*
  • Tetraodontiformes/metabolism*
PubMed
16565091 Full text @ J. Biol. Chem.
Abstract
Osteocalcin is a small, secreted bone protein whose gene consists of 4 exons. In the course of analyzing the structure of fish osteocalcin genes, we recently found that the spotted green pufferfish has two possible exon 2 structures, one of 15 bp and the other of 324 bp. Subsequent analysis of the pufferfish cDNA showed that only the transcript with a large exon 2 exists. Exon 2 codes for the osteocalcin propeptide, and exon 2 of pufferfish osteocalcin is about 3.4 fold larger than exon 2 previously found in other vertebrate species. We have termed this new pufferfish osteocalcin isoform OC2. Additional studies showed that the OC2 isoform is restricted to a unique fish taxonomic group, the Osteichthyes; OC2 is the only osteocalcin isoform found so far in 6 Osteichthyes species, while both OC1 and OC2 isoforms coexist in zebrafish and rainbow trout. The larger size of the OC2 propeptide is due to an acidic region that is likely to be highly phosphorylated and has no counter part in the OC1 propeptide. We propose: (1) that OC1 and OC2 are encoded by distinct genes that originated from a duplication event that probably occurred in the teleost fish lineage soon after divergence from tetrapods, and (2) that the novel OC2 propeptide could be, if secreted, a phosphoprotein that participates in the regulation of biomineralization through its large acidic and phosphorylated propeptide.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping