Interaction of steroids with nucleic acids

Abstract

17beta-Estradiol and testosterone bind to both native and denatured DNA, and to RNA and poly(A)-poly(U). Binding affinity depends on the conformation of nucleic acid. Lowering the electrolyte concentration and raising the temperature increase the binding of 17beta-estradiol to native DNA and decrease that to denatured DNA. In 0.01 M NaCl and at 37 degrees, more 17beta-estradiol is bound to native DNA than to denatured DNA. Higher binding of steroid to denatured DNA relative to native DNA at low temperature and high ionic strength is related to larger fraction of binding sites per unit nucleotide in denatured DNA. In addition to 17beta-estradiol and testosterone, 17alpha-estradiol, 17beta-estradiol-3-methyl ether and 19-nortestosterone also stabilize the structure of nucleic acids and poly(A)-poly(U) against thermal denaturation. The 17beta-estradiol induced elevation of the T-m of DNA is diminished by methanol or high NaCl concentration. These results indicate the involvement of hydrogen bonding and hydrophobic interactions between steroids and nucleic acids. The results of binding isotherms and optical studies suggest a conformational dependence of the binding of steroids to nucleic acids.

Organization of Polyoma Virus DNA in Mammary Tumours of Athymic Mice

“…ethanol was added. The DNA was spooled out of the mixture, dissolved in TNE and digested with RNase, followed by digestion with Pronase (Arya & Yang, 1975;Arya, i981). The solution was again extracted with phenol :chloroform :isoamyl alcohol followed by extraction with ether.…”

On the possible mode of regulation of DNA transcription by steroid hormones: Glucocorticoids

“…This immediately leads us to the interaction of steroids with DNA, the main target for transcriptional Although some reports are available on the binding of steroids to DNA [16][17][18] the biological relevance of this interaction is not known [7]. The steroid-DNA binding hypothesis was refuted by the observed in vitro binding of the receptor to W R E [ 19,201. However, in vivo studies showed the mandatory presence of steroids for receptor-HE interaction [21].…”