Transforming growth factor beta stimulation of biglycan gene expression is potentially mediated by sp1 binding factors
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Transforming growth factor beta stimulation of biglycan gene expression is potentially mediated by sp1 binding factors. / Heegaard, Anne-Marie; Xie, Zhongjian; Young, Marian Frances; Nielsen, Karina Lishmann.
I: Journal of Cellular Biochemistry, Bind 93, Nr. 3, 2004, s. 463-75.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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T1 - Transforming growth factor beta stimulation of biglycan gene expression is potentially mediated by sp1 binding factors
AU - Heegaard, Anne-Marie
AU - Xie, Zhongjian
AU - Young, Marian Frances
AU - Nielsen, Karina Lishmann
N1 - Copyright 2004 Wiley-Liss, Inc.
PY - 2004
Y1 - 2004
N2 - Biglycan is a small leucine-rich proteoglycan which is localized in the extracellular matrix of bone and other specialized connective tissues. Both biglycan mRNA and protein are up-regulated by transforming growth factor-beta(1) (TGF-beta(1)) and biglycan appears to influence TGF-beta(1) activity. In this study, we have investigated the mechanism by which TGF-beta(1), TGF-beta(2) and TGF-beta(3) stimulate biglycan mRNA expression in the osteoblastic cell line MG-63. The cells were transfected with a series of deletional human biglycan promoter constructs and a region in the biglycan 5' DNA was found to respond to TGF-beta(1) with increased transcriptional activity in a dose-dependent manner. Also TGF-beta(2) and TGF-beta(3), two structurally highly related TGF-beta isoforms stimulated biglycan transcription. A TGF-beta responsive region was identified within the first 218 bp of the human biglycan promoter upstream from the transcriptional start site, which contained several binding sites for the transcription factor Sp1. Electrophoretic mobility shift assays with nuclear extracts from MG-63 cells showed binding of both Sp1 and Sp3 to a site at -216 to -208. When the biglycan promoter construct was co-transfected with Sp1 and Sp3 expression vectors in Sp1-deficient Drosophila Schneider-2 cells, Sp1 induced the transcriptional activity of biglycan. Addition of Sp3 augmented the effect of Sp1 on biglycan gene expression. Induction of biglycan mRNA expression in response to TGF-beta in MG-63 cells was abrogated by mithramycin, an inhibitor of Sp1 binding to GC-rich DNA sequences. A mutation in the Sp1 site at -216 to -208 within the -218 biglycan promoter construct substantially diminished the transcriptional up-regulation by TGF-beta(1). Taken together this data shows for the first time that TGF-beta(1) stimulation of human biglycan mRNA expression relies on increased transcription of the biglycan gene, and is mediated by members of the Sp1 family of transcription factors.
AB - Biglycan is a small leucine-rich proteoglycan which is localized in the extracellular matrix of bone and other specialized connective tissues. Both biglycan mRNA and protein are up-regulated by transforming growth factor-beta(1) (TGF-beta(1)) and biglycan appears to influence TGF-beta(1) activity. In this study, we have investigated the mechanism by which TGF-beta(1), TGF-beta(2) and TGF-beta(3) stimulate biglycan mRNA expression in the osteoblastic cell line MG-63. The cells were transfected with a series of deletional human biglycan promoter constructs and a region in the biglycan 5' DNA was found to respond to TGF-beta(1) with increased transcriptional activity in a dose-dependent manner. Also TGF-beta(2) and TGF-beta(3), two structurally highly related TGF-beta isoforms stimulated biglycan transcription. A TGF-beta responsive region was identified within the first 218 bp of the human biglycan promoter upstream from the transcriptional start site, which contained several binding sites for the transcription factor Sp1. Electrophoretic mobility shift assays with nuclear extracts from MG-63 cells showed binding of both Sp1 and Sp3 to a site at -216 to -208. When the biglycan promoter construct was co-transfected with Sp1 and Sp3 expression vectors in Sp1-deficient Drosophila Schneider-2 cells, Sp1 induced the transcriptional activity of biglycan. Addition of Sp3 augmented the effect of Sp1 on biglycan gene expression. Induction of biglycan mRNA expression in response to TGF-beta in MG-63 cells was abrogated by mithramycin, an inhibitor of Sp1 binding to GC-rich DNA sequences. A mutation in the Sp1 site at -216 to -208 within the -218 biglycan promoter construct substantially diminished the transcriptional up-regulation by TGF-beta(1). Taken together this data shows for the first time that TGF-beta(1) stimulation of human biglycan mRNA expression relies on increased transcription of the biglycan gene, and is mediated by members of the Sp1 family of transcription factors.
KW - Animals
KW - Biglycan
KW - Cell Nucleus
KW - Cells, Cultured
KW - DNA-Binding Proteins
KW - Drosophila
KW - Electrophoretic Mobility Shift Assay
KW - Extracellular Matrix Proteins
KW - Humans
KW - Mutation
KW - Promoter Regions, Genetic
KW - Proteoglycans
KW - Sp1 Transcription Factor
KW - Sp3 Transcription Factor
KW - Transcription Factors
KW - Transcription, Genetic
KW - Transforming Growth Factor beta
KW - Transforming Growth Factor beta1
KW - Transforming Growth Factor beta2
KW - Transforming Growth Factor beta3
U2 - 10.1002/jcb.20189
DO - 10.1002/jcb.20189
M3 - Journal article
C2 - 15372625
VL - 93
SP - 463
EP - 475
JO - Journal of cellular biochemistry. Supplement
JF - Journal of cellular biochemistry. Supplement
SN - 0733-1959
IS - 3
ER -
ID: 38426279