Cloning of mouse diastrophic dysplasia sulfate transporter gene induced during osteoblast differentiation by bone morphogenetic protein-2.
Although intensive studies have been directed at understanding osteoblastic differentiation, the molecular mechanisms are still unclear. In this study, we describe a cDNA that encodes a sulfate transporter that was cloned as a gene induced in osteoblast precursor cells in association with osteoblastic differentiation. Based on the fact that bone morphogenetic protein-2 (BMP-2) induces osteoblastic phenotypes in immature mouse fibroblastic C3H10T1/2 cells, we performed a subtraction hybridization between BMP-2-treated and untreated cells, and have isolated one clone (designated as st-ob for sulfate transporter in osteoblast) induced by BMP-2 that is constantly expressed in osteoblastic cells. The deduced amino acid sequence and proposed structure of st-ob are mostly identical to those of the human diastrophic dysplasia sulfate transporter gene product (DTDST). St-ob mRNA was abundantly expressed in the thymus, testis, calvaria and osteoblastic MC3T3-E1 cells, whereas its expression was faint in C3H10T1/2 cells. Expression of st-ob in C3H10T1/2 cells was increased by transforming growth factor-beta1 (TGF-beta1), retinoic acid and dexamethasone as well as BMP-2. Furthermore, BMP-2 increased sulfate incorporation in C3H10T1/2 cells about twice as high as the baseline level. Osteoblasts actively take up sulfate to synthesize proteoglycans, which are one of the major components of the extracellular matrix of bone and cartilage. The present study demonstrates that st-ob induced during osteoblastic differentiation is an important phenotype of osteoblasts for characterizing their function.
Kobayashi
T
T
Department of Medicine, Kobe University, School of Medicine, Japan.
Sugimoto
T
T
Saijoh
K
K
Fukase
M
M
Chihara
K
K
D000818:Animals; D027321:Anion Transport Proteins; D001483:Base Sequence; D001692:Biological Transport; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D002352:Carrier Proteins / Q000235:genetics*; D002454:Cell Differentiation; D002460:Cell Line; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics; D026901:Membrane Transport Proteins; D051379:Mice; D008969:Molecular Sequence Data; D010006:Osteoblasts / Q000166:cytology*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D000076988:Sulfate Transporters; D013431:Sulfates / Q000378:metabolism*; D014018:Tissue Distribution
D027321:Anion Transport Proteins; D019485:Bone Morphogenetic Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; C089651:SLC26A2 protein, human; C513264:Slc26a2 protein, mouse; D000076988:Sulfate Transporters; D013431:Sulfates