Synergistic activation of a human promoter in vivo by transcription factor Sp1
- Henry Ford Hospital, Detroit, MI (United States)
- University of Michigan, Ann Arbor (United States)
Many eucaryotic promoters contain multiple binding sites for sequence-specific DNA-binding proteins. In some cases, these proteins have been shown to interact synergistically to activate transcription. In this study, the authors address the possibility that the transcription factor Sp1 can synergistically activate a native human promoter in a cellular context that closely resembles that of a single-copy gene. Using DNase I footprinting with affinity-purified Sp1, they show that the human argininosuccinate synthetase (AS) promoter contains three sites that bind Sp1 with different affinities. These binding sites were mutated to abolish Sp1 binding, individually and in all possible combinations, to generate a series of AS promoter-CAT constructs was then measured in stably transfected human RPMI 2650 cells lines. The results show that each of the three Sp1-binding sites contributes to full activation of the human AS promoter and the relative contribution of each site correlates well with its in vitro affinity for Sp1. They provide direct evidence that Sp1-binding sites in their native context in a human promoter can interact synergistically in vivo to activate transcription. The ability to activate transcription synergistically may be the reason that many cellular promoters have multiple Sp1-binding sites arranged in tandem and in close proximity.
- OSTI ID:
- 6969204
- Journal Information:
- Molecular and Cellular Biology; (United States), Vol. 11:4; ISSN 0270-7306
- Country of Publication:
- United States
- Language:
- English
Similar Records
Genetic Selection for Context-Dependent Stochastic Phenotypes: Sp1 and TATA Mutations Increase Phenotypic Noise in HIV-1 Gene Expression
DNA looping and Sp1 multimer links: A mechanism for transcriptional synergism and enhancement
Related Subjects
GENE REPRESSORS
CONFIGURATION INTERACTION
LIGASES
GENE REGULATION
TRANSCRIPTION FACTORS
DNA-ASE
RNA POLYMERASES
ENZYMES
ESTERASES
HYDROLASES
NUCLEOTIDYLTRANSFERASES
ORGANIC COMPOUNDS
PHOSPHODIESTERASES
PHOSPHORUS-GROUP TRANSFERASES
POLYMERASES
PROTEINS
TRANSFERASES
550200* - Biochemistry