Enhancer and promoter elements directing activation and glucocorticoid repression of the. cap alpha. /sub 1/-fetoprotein gene in hepatocytes
Mutations were introduced in 7 kilobases of 5'-flanking rat ..cap alpha../sub 1/-fetoprotein (AFP) genomic DNA, linked to the chloramphenicol acetyltransferase gene. AFP promoter activity and its repression by a glucocorticoid hormone were assessed by stable and transient expression assays. Stable transfection assays were more sensitive and accurate than transient expression assays in a Morris 7777 rat hepatoma recipient (Hepa7.6), selected for its strong AFP repression by dexamethasone. The segment of DNA encompassing a hepatocyte-constitutive chromatin DNase I-hypersensitive site at -3.7 kilobases and a liver developmental stage-specific site at -2.5 kilobases contains interacting enhancer elements sufficient for high AFP promoter activity in Hepa7.6 or HepG2 cells. Deletions and point mutations define an upstream promoter domain of AFP gene activation, operating with at least three distinct promoter-activating elements, PEI at -65 base pairs, PEII at -120 base pairs, and DE at -160 base pairs. PEI and PEII share homologies with albumin promoter sequences, PEII is a near-consensus nuclear factor I recognition sequence, and DE overlaps a glucocorticoid receptor recognition sequence. An element conferring glucocorticoid repression of AFP gene activity is located in the upstream AFP promoter domain. Receptor-binding assays indicate that this element is the glucocorticoid receptor recognition sequence which overlaps with promoter-activating element DE.
- Research Organization:
- Le Centre de Recherche en Cancerologie de l'Universite Laval, L'Hotel-Dieu de Quebec, Quebec G1R 2J6 (CA)
- OSTI ID:
- 7192090
- Journal Information:
- Mol. Cell. Biol.; (United States), Vol. 8:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GLUCOCORTICOIDS
BIOLOGICAL PATHWAYS
LIVER CELLS
BIOLOGICAL FUNCTIONS
PROTEINS
MUTATIONS
TRANSFERASES
GENES
CHLORAMPHENICOL
CHROMATIN
DNA SEQUENCING
DNA-ASE
FETUSES
GENE AMPLIFICATION
HEPATOMAS
PHENOTYPE
RATS
ADRENAL HORMONES
ANIMAL CELLS
ANIMALS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
CORTICOSTEROIDS
DISEASES
DRUGS
ENZYMES
ESTERASES
FUNCTIONS
HYDROLASES
HYDROXY COMPOUNDS
KETONES
MAMMALS
NEOPLASMS
ORGANIC COMPOUNDS
PHOSPHODIESTERASES
PREGNANES
RODENTS
SOMATIC CELLS
STEROIDS
STRUCTURAL CHEMICAL ANALYSIS
VERTEBRATES
550200* - Biochemistry