TY - JOUR
T1 - Transcriptional regulation of alpha 2(I) collagen gene expression by fibroblast growth factor-2 in MC3T3-E1 osteoblast-like cells
AU - Fang, Meika A.
AU - Glackin, Carlotta A.
AU - Sadhu, Archana
AU - McDougall, Skye
PY - 2001/3/15
Y1 - 2001/3/15
N2 - Fibroblast growth factor-2 (FGF-2) stimulates proliferation and inhibits differentiated function of osteoblasts by suppressing synthesis of type I collagen and other proteins. However, little is known regarding the molecular mechanisms regulating the suppressive effects of FGF-2 on type I collagen synthesis in osteoblasts. The zinc finger transcription factor Egr-1 and the basic helix-loop-helix (bHLH) family of proteins have been implicated in the regulation of genes crucial to mesodermal cell growth and differentiation. The aim of this study was to determine whether Egr-1 and TWIST might be potential transcriptional regulators of the inhibitory effects of FGF-2 on α2(I) collagen expression in MC3T3-E1 osteoblasts which undergo a developmental sequence in vitro. Upon treatment of undifferentiated MC3T3-E1 cells with 1 nM FGF-2, Egr-1 mRNA increased with the effect maximal after 30-60min. TWIST mRNA also increased with the effect maximal at 2 h. We analyzed the transcriptional control of α2(I) collagen gene expression by FGF-2 by transient transfection of an α2(I) collagen-luciferase construct (pH5) into undifferentiated MC3T3-E1 cells. The activity of the pH5 luciferase promoter decreased in a dose-dependent manner following treatment with.01 and 1 nM FGF-2. We identified putative Egr-1 and TWIST recognition sequences in the proximal region of the promoter for the murine α2(I) collagen gene and a putative Egr-1 site in the 5′ region of the murine TWIST promoter. In gel mobility shift assays, potential Egr-1 response elements in the 5′ region of the murine TWISTand α2(1) collagen genes demonstrated specific Egr-1 binding activity with bFGF-treated nuclear extracts obtained from MC3T3-E1 cells. These results indicate that Egr-1 and TWIST are expressed in undifferentiated MC3T3-E1 osteoblast-like cells following treatment with FGF-2 and they may be potential transcriptional regulators of FGF-2s negative effects on α2(I) collagen gene expression. Published 2001 Wiley-Liss, Inc.
AB - Fibroblast growth factor-2 (FGF-2) stimulates proliferation and inhibits differentiated function of osteoblasts by suppressing synthesis of type I collagen and other proteins. However, little is known regarding the molecular mechanisms regulating the suppressive effects of FGF-2 on type I collagen synthesis in osteoblasts. The zinc finger transcription factor Egr-1 and the basic helix-loop-helix (bHLH) family of proteins have been implicated in the regulation of genes crucial to mesodermal cell growth and differentiation. The aim of this study was to determine whether Egr-1 and TWIST might be potential transcriptional regulators of the inhibitory effects of FGF-2 on α2(I) collagen expression in MC3T3-E1 osteoblasts which undergo a developmental sequence in vitro. Upon treatment of undifferentiated MC3T3-E1 cells with 1 nM FGF-2, Egr-1 mRNA increased with the effect maximal after 30-60min. TWIST mRNA also increased with the effect maximal at 2 h. We analyzed the transcriptional control of α2(I) collagen gene expression by FGF-2 by transient transfection of an α2(I) collagen-luciferase construct (pH5) into undifferentiated MC3T3-E1 cells. The activity of the pH5 luciferase promoter decreased in a dose-dependent manner following treatment with.01 and 1 nM FGF-2. We identified putative Egr-1 and TWIST recognition sequences in the proximal region of the promoter for the murine α2(I) collagen gene and a putative Egr-1 site in the 5′ region of the murine TWIST promoter. In gel mobility shift assays, potential Egr-1 response elements in the 5′ region of the murine TWISTand α2(1) collagen genes demonstrated specific Egr-1 binding activity with bFGF-treated nuclear extracts obtained from MC3T3-E1 cells. These results indicate that Egr-1 and TWIST are expressed in undifferentiated MC3T3-E1 osteoblast-like cells following treatment with FGF-2 and they may be potential transcriptional regulators of FGF-2s negative effects on α2(I) collagen gene expression. Published 2001 Wiley-Liss, Inc.
KW - Egr-1
KW - FGF-2
KW - Helix-loop-helix
KW - Osteoblast
KW - Transcription factor
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U2 - 10.1002/1097-4644(20010315)80:4<550::AID-JCB1009>3.0.CO;2-1
DO - 10.1002/1097-4644(20010315)80:4<550::AID-JCB1009>3.0.CO;2-1
M3 - Article
C2 - 11169739
SN - 0730-2312
VL - 80
SP - 550
EP - 559
JO - Journal of Cellular Biochemistry
JF - Journal of Cellular Biochemistry
IS - 4
ER -