Fang, Meika A.
(Geriatric Research, Education and Clinical Center, VA Greater Los Angeles Healthcare System, Los Angeles, California 90073)
,
Glackin, Carlotta A.
(Division of Molecular Medicine, City of Hope National Medical Center, Duarte, California 91010)
,
Sadhu, Archana
(Geriatric Research, Education and Clinical Center, VA Greater Los Angeles Healthcare System, Los Angeles, California 90073)
,
McDougall, Skye
(Geriatric Research, Education and Clinical Center, VA Greater Los Angeles Healthcare System, Los Angeles, California 90073)
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 s...
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 30–60 min. 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 TWIST and α2(I) 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. J. Cell. Biochem. 80:550–559, 2001. Published 2001 Wiley-Liss, Inc.
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 30–60 min. 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 TWIST and α2(I) 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. J. Cell. Biochem. 80:550–559, 2001. Published 2001 Wiley-Liss, Inc.
AI-Helper
※ AI-Helper는 부적절한 답변을 할 수 있습니다.