Dentin sialoprotein in bone and dentin sialophosphoprotein gene expressed by osteoblasts.
Dentin sialoprotein (DSP) and dentin phosphoprotein (DPP) are expressed as a single mRNA transcript. This transcript codes for a large precursor protein termed dentin sialophosphoprotein (DSPP). DSP, DPP, and DSPP have been considered to be tooth-specific. Recently, we found out that the dspp gene was expressed in osteoblasts and bone. With Western immunoblots, we detected DSP in the Gdm/EDTA extracts of rat long bone, at a level of about 1/400 of that in dentin. Using reverse transcription polymerase chain reaction (RT-PCR) techniques with primers specific to the 5'DSP portion (termed DSP, 1432 bp), 3'DPP sequence (DPP, 2135 bp), and the region covering portions of both the DSP and DPP (DSPP, 3471 bp), we detected DSPP mRNA in MC3T3-E1 cells, ROS 17/2.8 osteoblast-like cells, and mouse calvaria. The results from PCR show that this gene is expressed at a much lower level in osteoblasts than in odontoblasts. The data indicate that DSPP is not a tooth-specific protein and that dramatically different regulatory mechanisms governing DSPP expression are involved in tooth and bone.
Qin
Chunlin
C
Department of Basic Sciences, University of Texas-Houston Health Science Center Dental Branch, Houston, Texas 77030, USA. cqin@mail.db.uth.tmc.edu
Brunn
Jan C
JC
Cadena
Elizabeth
E
Ridall
Amy
A
Butler
William T
WT
D000818:Animals; D015153:Blotting, Western; D001842:Bone and Bones / Q000378:metabolism*; D002113:Calcification, Physiologic / Q000502:physiology; D002478:Cells, Cultured; D016326:Extracellular Matrix Proteins; D015870:Gene Expression; D051379:Mice; D009804:Odontoblasts / Q000378:metabolism; D010006:Osteoblasts / Q000378:metabolism*; D010750:Phosphoproteins; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism*; D000099311:Dentin Sialophosphoprotein
D016326:Extracellular Matrix Proteins; D010750:Phosphoproteins; D011498:Protein Precursors; D012333:RNA, Messenger; D012795:Sialoglycoproteins; D000099311:Dentin Sialophosphoprotein