A twenty-two-fold increase in the relative affinity of estrogen receptor to poly (dA-dC)•poly (dG-dT) in the presence of polyamines

• Published in: Nucleic acids research 1988-05, Vol.16 (10), p.4705-4720
• Main Authors: THOMAS, T, KIANG, D. T
• Format: Article
• Language: English
• Subjects: Animals; Binding, Competitive; Biological and medical sciences; Cell physiology; Chromatography, Affinity - methods; Cytosol - metabolism; DNA - pharmacology; Female; Fundamental and applied biological sciences. Psychology; Hormonal regulation; Kinetics; Molecular and cellular biology; Polydeoxyribonucleotides - metabolism; Putrescine - pharmacology; Rabbits; Receptors, Estrogen - drug effects; Receptors, Estrogen - isolation & purification; Receptors, Estrogen - metabolism; Spermidine - pharmacology; Spermine - pharmacology; Uterus - metabolism
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/16.10.4705

We studied the relative efficacy of polyamines to facilitate the binding of estrogen receptor to poly(dA-dC).poly(dG-dT). In the absence of polyamines, 1,400 micrograms/ml of this polynucleotide eluted 50% of bound estrogen receptor from DNA-cellulose. In contrast, 50% estrogen receptor was eluted by 65 micrograms/ml of poly(dA-dC).poly(dG-dT) complexed with 150 microM spermidine. Putrescine and spermine also enhanced the ability of poly(dA-dC).poly(dG-dT) to elute estrogen receptor, but the magnitude of the effect was not as high as that of spermidine. Control experiments with calf thymus DNA and poly(dA-dT).poly(dA-dT) showed 6- and 3-fold increase, respectively in their affinity for estrogen receptor in the presence of spermidine. The dramatic increase in the affinity of poly(dA-dC).poly(dG-dT) for estrogen receptor in the presence of polyamines might be a result of the conversion of the polynucleotide to the left-handed Z-DNA form. These results show that polyamines are capable of participating in estrogenic regulation of gene expression by altering the affinity of the receptor for specific DNA sequences.