Related Experiment Video
Updated: Aug 12, 2026
Culture of Murine Embryonic Metatarsals: A Physiological Model of Endochondral Ossification
Published on: December 3, 2016
Cloning of mouse diastrophic dysplasia sulfate transporter gene induced during osteoblast differentiation by bone
T Kobayashi1, T Sugimoto, K Saijoh
1Department of Medicine, Kobe University, School of Medicine, Japan.
Abstract:
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.
Insights
A novel sulfate transporter gene, st-ob, is induced during osteoblastic differentiation. This gene is crucial for osteoblast function, particularly sulfate uptake for proteoglycan synthesis in bone.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Osteoblastic differentiation is critical for bone formation, but its underlying molecular mechanisms remain incompletely understood.
- Sulfate transport is essential for synthesizing proteoglycans, key components of the bone extracellular matrix.
Purpose of the Study:
- To identify and characterize novel genes involved in osteoblastic differentiation.
- To investigate the role of a newly identified sulfate transporter (st-ob) in osteoblast function.
Main Methods:
- Subtraction hybridization was used to identify genes induced by bone morphogenetic protein-2 (BMP-2) in osteoblast precursor cells.
- Quantitative analysis of st-ob mRNA expression in various tissues and cell lines.
- Assessment of sulfate incorporation in response to BMP-2 stimulation.
Main Results:
- A cDNA encoding a sulfate transporter, designated st-ob, was identified and found to be induced during osteoblastic differentiation.
- st-ob shares high sequence identity with the human diastrophic dysplasia sulfate transporter (DTDST).
- st-ob expression is upregulated by BMP-2, TGF-beta1, retinoic acid, and dexamethasone, and BMP-2 significantly increases sulfate uptake in cells.
Conclusions:
- The st-ob gene is a novel marker and functional component of osteoblastic differentiation.
- st-ob plays a significant role in facilitating sulfate transport, essential for proteoglycan synthesis and bone matrix formation.
- Understanding st-ob function provides new insights into the molecular regulation of osteogenesis.
