title: Expression and function of periostin-isoforms in bone.
abstract: 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.
authors.affiliation: Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA. jl1@temple.edu
authors.forename: Judith
authors.initials: J
authors.lastname: Litvin
authors.forename: Abdul-Hafez
authors.initials: AH
authors.lastname: Selim
authors.forename: Michael O
authors.initials: MO
authors.lastname: Montgomery
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Lehmann
authors.forename: Mario C
authors.initials: MC
authors.lastname: Rico
authors.forename: Hugh
authors.initials: H
authors.lastname: Devlin
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Bednarik
authors.forename: Fayez F
authors.initials: FF
authors.lastname: Safadi
mesh_terms: 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
chemical_list: D015815:Cell Adhesion Molecules; D018076:DNA, Complementary; C082838:Postn protein, mouse; D020033:Protein Isoforms; D012333:RNA, Messenger