Autoregulation of bone sialoprotein gene in pre-osteoblastic and non-osteoblastic cells

• Published in: Biochemical and biophysical research communications 2004-04, Vol.316 (2), p.461-467
• Main Authors: Tu, Qisheng, Yamauchi, Masato, Pageau, Steven C, Chen, Jake (Jinkun)
• Format: Article
• Language: English
• Subjects: Animals; BSP; BSP autoregulation; Cbfa1; Cell Line; Coculture Techniques; Cytomegalovirus - genetics; Genetic Vectors; Homeostasis; Humans; Integrin-Binding Sialoprotein; Mice; Osteoblasts; Osteoblasts - metabolism; Promoter; Promoter Regions, Genetic; Regulatory Sequences, Nucleic Acid; RNA, Messenger - metabolism; Sialoglycoproteins - genetics; Sialoglycoproteins - metabolism; Stem Cells - metabolism; TPA; Transcriptional Activation
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2004.02.068

Regulation of the bone sialoprotein (BSP) gene is important in the differentiation of osteoblasts, in bone matrix mineralization, and in tumor metastasis. We investigated BSP gene transcription by performing functional analysis of the 9256 bp of the 5 ′ flanking region of the murine BSP gene containing its promoter. We found that the forced expression of BSP stimulated mouse BSP promoter activity in a dose-dependent manner in both MC3T3-E1 preosteoblast and HEK-293 cell lines, which was transcriptional factor Cbfa1 independent. Co-culture of cells separately expressing BSP promoter reporter and BSP failed to mediate the BSP autoregulation, suggesting that the event might happen intracellularly. Deletion analysis of the BSP promoter indicated that the proximal promoter (110 bp) was sufficient to confer this autoregulation. We conclude that the BSP gene is autoregulated in part by a positive feedback on its own promoter.