AGP/EBP(LAP) expressed in rat hepatoma cells interacts with multiple promoter sites and is necessary for maximal glucocorticoid induction of the rat alpha-1 acid glycoprotein gene.
Transcription of the rat alpha 1-acid glycoprotein (AGP) gene is induced by glucocorticoids. In addition to the glucocorticoid response element which maps to bases -120 to -107, sequences located between bases -106 to -42 have been shown to be necessary for hormone induction. We have previously identified multiple sites of C/EBP interaction with the AGP promoter in the region -106 to -64. In this study, we purify and identify a C/EBP family member, AGP/EBP(LAP), present in the rat hepatoma cell line HTC (JZ.1) which also binds to the C/EBP recognition sites in this region. Mutations in the recognition sites that prevent binding are analyzed, and the results suggest a positive as well as a possible inhibitory role for AGP/EBP(LAP) in the glucocorticoid induction of the gene in HTC (JZ.1) cells.
Williams
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P
Syntex Research, Palo Alto, California 94304.
Ratajczak
T
T
Lee
S C
SC
Ringold
G M
GM
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000502:physiology; D015153:Blotting, Western; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D003907:Dexamethasone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D005938:Glucocorticoids / Q000494:pharmacology*; D015292:Glycoprotein Hormones, alpha Subunit / Q000235:genetics / Q000502:physiology*; D008114:Liver Neoplasms, Experimental; D008969:Molecular Sequence Data; D009154:Mutation / Q000502:physiology; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D009961:Orosomucoid / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000502:physiology; D051381:Rats; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014407:Tumor Cells, Cultured
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D005938:Glucocorticoids; D015292:Glycoprotein Hormones, alpha Subunit; D009687:Nuclear Proteins; D009961:Orosomucoid; D014157:Transcription Factors; D003907:Dexamethasone