Identification and characterization of integrin-binding sialoprotein (IBSP) genes in reptile and amphibian.
Integrin-binding sialoprotein (IBSP) is a member of the small integrin-binding ligand N-linked glycoprotein (SIBLING) family; and the whole SIBLING family is further included in a larger secretory calcium-binding phosphoprotein (SCPP) family. SIBLING proteins are known to construct a part of the non-collagenous extracellular matrices of calcified tissues, and considered to have arisen by duplication and subsequent divergent evolution of a single ancient gene. To understand the alterations of SIBLING molecules associated with the evolution of calcified tissues in vertebrates, we initiated a search for lower vertebrate orthologs of SIBLING genes. In the present study, an IBSP ortholog from a reptile (caiman) and two distinct orthologs from an amphibian (African clawed toad) were identified and characterized. As expected, the toad IBSP genes were transcribed only in calcified tissue (jaw and tibia), as also seen in mammals. The caiman, toad, avian, and mammalian IBSPs share several unique features specific for IBSP and apparently have similar properties. Furthermore, analysis of the sequences suggested that the IBSP molecule might have gradually intensified its functions related to calcification during its evolutionary process through tetrapods.
Shintani
Seikou
S
Department of Pediatric Dentistry, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba 261-8502, Japan. sshintani@tdc.ac.jp
Kamakura
Naofumi
N
Kobata
Mitsuhiko
M
Toyosawa
Satoru
S
Onishi
Tomoyuki
T
Sato
Akie
A
Kawasaki
Kazuhiko
K
Weiss
Kenneth M
KM
Ooshima
Takashi
T
D000489:Alligators and Crocodiles / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics*; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D058574:Integrin-Binding Sialoprotein; D008322:Mammals / Q000235:genetics; D008969:Molecular Sequence Data; D010448:Peptide Initiation Factors / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D012313:RNA / Q000235:genetics; D012795:Sialoglycoproteins / Q000235:genetics*; D014982:Xenopus laevis / Q000235:genetics*
D017931:DNA Primers; D018076:DNA, Complementary; C546871:IBSP protein, human; D058574:Integrin-Binding Sialoprotein; D010448:Peptide Initiation Factors; D012795:Sialoglycoproteins; D012313:RNA; D004247:DNA