Assembly of a glucocorticoid receptor complex prior to DNA binding enhances its specific interaction with a glucocorticoid response element

• Published in: The Journal of biological chemistry Vol. 266; no. 17; pp. 11221 - 11226
• Main Authors: CAIRNS, W, CAIRNS, C, PONGRATZ, I, POELLINGER, L, OKRET, S
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Biochemistry and Molecular Biology 15-06-1991
• Subjects: Animals; Base Sequence; Binding Sites; Binding, Competitive; Biological and medical sciences; Cell receptors; Cell structures and functions; Cytosol - metabolism; DNA - metabolism; DNA-Binding Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Hormone receptors. Growth factor receptors. Cytokine receptors. Prostaglandin receptors; Humans; Kinetics; Liver - metabolism; Macromolecular Substances; Molecular and cellular biology; Molecular Sequence Data; Mutagenesis, Site-Directed; Oligodeoxyribonucleotides - chemical synthesis; Rats; Receptors, Glucocorticoid - isolation & purification; Receptors, Glucocorticoid - metabolism; Vertebrata; Mammalia; Binding capacity; Rat; DNA; Rodentia; Regulatory sequence; Gel retardation technique; Transcription factor; Glucocorticoid; Hormonal receptor
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)99151-9

Gel retardation analysis with full- and half-palindromic sequences using partially purified glucocorticoid receptor (GR) resulted
in GR-glucocorticoid response element (GRE) species of identical mobilities, suggesting that formation of the dimeric GR protein
complex is not catalyzed by DNA binding. These results are in contrast to the behavior of the isolated DNA binding domain
of the glucocorticoid receptor where dimerization occurred on the GRE. Density gradient centrifugation of cytosolic GR resulted
in two forms, a 4 S peak characteristic of the monomeric GR and a fraction which sediments at 6 S which is consistent with
the observed size of the dimeric GR. These two forms were found to differ in their ability to bind to specific DNA sequences
with the 6 S species having a higher affinity for a GRE. Taken together our results are consistent with a two-step model for
hormone-induced transformation of GR: dissociation of the multimeric untransformed complex and dimerization of the GR to yield
a high affinity DNA binding species.