TY - JOUR
T1 - Role of the transcription factor Sox-2 in the expression of the FGF-4 gene in embryonal carcinoma cells
AU - Johnson, Lance R.
AU - Lamb, Kimberly A.
AU - Gao, Qingsheng
AU - Nowling, Tamara K.
AU - Rizzino, Angie
PY - 1998/8
Y1 - 1998/8
N2 - It has been shown previously that the FGF-4 gene is regulated by a powerful downstream enhancer in embryonal carcinoma (EC) cells. This enhancer contains an essential HMG motif; however, the transcription factor that binds to the HMG motif in EC cells has not been determined definitively. In earlier studies, this HMG motif was shown to bind a heat-stable, redox-insensitive factor expressed by F9 EC cells. Others have proposed that the transcription factor Sox-2 binds to the FGF4 enhancer HMG motif. In this study, we demonstrate that the N-terminal half of Sox-2, which contains the DNA binding domain, binds to the FGF-4 enhancer HMG motif and we show that this binding is unaffected by heat and oxidation. In addition, we employed two experimental approaches to demonstrate that Sox-2 regulates the transcription of the FGF-4 gene in EC cells. As part of these studies, an expression plasmid that codes for a dominant-negative form of Sox-2 was used in transient expression assays. In other experiments, a Sox-2 antisense expression plasmid was used. When co-transfected into F9 EC cells along with an FGF-4 promoter/reporter gene construct, each expression plasmid caused a significant reduction in reporter activity. Our studies also demonstrate that Sox-2 affects the expression of the FGF-4 gene in the multipotent EC cell line, P19. Taken together, these studies argue strongly that Sox-2 plays an important role in the expression of the FGF-4 gene in vivo.
AB - It has been shown previously that the FGF-4 gene is regulated by a powerful downstream enhancer in embryonal carcinoma (EC) cells. This enhancer contains an essential HMG motif; however, the transcription factor that binds to the HMG motif in EC cells has not been determined definitively. In earlier studies, this HMG motif was shown to bind a heat-stable, redox-insensitive factor expressed by F9 EC cells. Others have proposed that the transcription factor Sox-2 binds to the FGF4 enhancer HMG motif. In this study, we demonstrate that the N-terminal half of Sox-2, which contains the DNA binding domain, binds to the FGF-4 enhancer HMG motif and we show that this binding is unaffected by heat and oxidation. In addition, we employed two experimental approaches to demonstrate that Sox-2 regulates the transcription of the FGF-4 gene in EC cells. As part of these studies, an expression plasmid that codes for a dominant-negative form of Sox-2 was used in transient expression assays. In other experiments, a Sox-2 antisense expression plasmid was used. When co-transfected into F9 EC cells along with an FGF-4 promoter/reporter gene construct, each expression plasmid caused a significant reduction in reporter activity. Our studies also demonstrate that Sox-2 affects the expression of the FGF-4 gene in the multipotent EC cell line, P19. Taken together, these studies argue strongly that Sox-2 plays an important role in the expression of the FGF-4 gene in vivo.
KW - Cis-regulatory element
KW - Fibroblast growth factor
KW - Gel mobility shift analysis
KW - Transient expression assay
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U2 - 10.1002/(SICI)1098-2795(199808)50:4<377::AID-MRD1>3.0.CO;2-F
DO - 10.1002/(SICI)1098-2795(199808)50:4<377::AID-MRD1>3.0.CO;2-F
M3 - Article
C2 - 9669521
AN - SCOPUS:0031750323
SN - 1040-452X
VL - 50
SP - 377
EP - 386
JO - Molecular Reproduction and Development
JF - Molecular Reproduction and Development
IS - 4
ER -