Expression and function of periostin-isoforms in bone.
Periostin was originally identified in MC3T3-E1 osteoblast-like cells. We have identified an isoform of periostin referred to as periostin-like-factor (PLF). It is homologous to other proteins such as fasciclin I (fas I), MPB70, betaIG-H3, and Algal-CAMs. All of these proteins are implicated in regulating cell adhesion. PLF and the other isoforms of periostin differ in their C-terminal sequences. PLF and periostin differ in two specific regions, between 673 and 699 amino acids (aa) and 785-812 aa. Periostin isoforms are expressed in vivo and in vitro during the stages of osteoblast differentiation and maturation. Their mRNAs are present in pre-osteoblast cells as detected by in situ hybridization, and the proteins are between 86 and 93 kD in size as determined by Western blot analysis. Antisense oligonucleotides and antibodies directed against the isoforms of periostin were used to block the activity of these proteins. In both cases, the levels of osteoblast-specific-differentiation markers were markedly reduced suggesting a role for these proteins in osteoblast differentiation.
Litvin
Judith
J
Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA. jl1@temple.edu
Selim
Abdul-Hafez
AH
Montgomery
Michael O
MO
Lehmann
Kiyoko
K
Rico
Mario C
MC
Devlin
Hugh
H
Bednarik
Daniel P
DP
Safadi
Fayez F
FF
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D003001:Cloning, Molecular; D018076:DNA, Complementary; D047108:Embryonic Development / Q000235:genetics; D017403:In Situ Hybridization; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid
D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; C082838:Postn protein, mouse; D020033:Protein Isoforms; D012333:RNA, Messenger