Effect of Cibacron blue F3GA on oligonucleotide binding site of estradiol--receptor complexes of mouse uterine cytosol.

Abstract

It is believed that steroid hormones induce differential gene expression in target cells by combining with specific cytoplasmic receptor proteins that subsequently translocate to the nuclear compartment where they interact with a limited number of acceptor sites (1). Although the nature of these nuclear acceptor sites is still unclear, it is well established that almost all steroid receptors described are able to combine with DNA (2-4). Andre and Rochefort (5) have demonstrated that the affinity of the estradiol receptor protein for DNA is increased by estrogen binding, analogous to the ligand-induced DNA binding property of cyclic AMP receptor protein, a prokaryotic gene regulatory protein (6). Several lines of evidence suggest that steroid receptor proteins, particularly estradiol and glucocorticoid receptor proteins, contain two distinct sites, one for the steroid hormone and the other for DNA. Limited proteolysis of the steroid receptor protein complexes destroys the DNA binding site without affecting the steroid binding site (7-9). In addition, compounds such as pyridoxal phosphate (10) and aurintricarboxylic acid (ATA) (11) have been shown to inhibit DNA binding of glucocorticoid and estradiol receptor proteins, respectively.Studies reported from this laboratory have shown that estradiol-receptor complexes (E2R) of mouse uterus and kidney bind to oligo(dT)-cellulose. The validity of this interaction as a model for the DNA binding property of estradiol-receptors has been well established (12). Using oligo(dT)-cellulose binding as an assay for DNA interaction, we studied the inhibitory effect of the dye Cibacron blue F3GA (CB) in order to characterize the DNA recognition site. CB, a sulfonated polyaromatic dye, has been shown to bind to several proteins that interact with nucleotide substrates, nucleotide coenzyme ligands, and polynucleotides (13)(14)(15)(16)(17)(18). In the case of enzymes that have polynucleotide binding sites in addition to nucleotide substrates, the dye interacts with the polynucleotide binding site preferentially (15,17,18). In the present study we have shown that CB interacts specifically with the DNA binding domain of the mouse uterine E2R. MATERIALS AND METHODS[3H]Estradiol (145 Ci/mol; 1 Ci = 3.7 X 1010 becquerels) was obtained from Amersham. Unlabeled estradiol was a product of Steraloids, Inc. (Wilton, NH). Olido(dT)-, oligo(dC)-, and oligo(dA)-celluloses were products of P-L Biochemicals. Calf thymus DNA and heparin were obtained from Sigma. Poly-L-glutamic acid was a product of Miles-Yeda (Rehovoth, Israel), and CB was a gift from CIBA (Basel, Switzerland). (vol/vol) glycerol with a Polytron P20ST homogenizer. The homogenate was centrifuged in a Beckman J-21 centrifuge with JA-20 rotor at 12,000 X g for 10 min, and the supernatant was recentrifuged at 300,000 X g for 60 min in a Beckman preparative ultracentrifuge (L-75) with a 75 Ti rotor. The supernatant fraction is referred to as the "cytosol." Testosterone (1.2 ,uM)

Activation, Transformation, and Subunit Structure of Steroid Hormone Receptors

“…This sulfonated polyaromatic dye is thought to interact with the "dinucleotide fold" of DNA-binding proteins. It has been reported to inhibit DNA-cellulose binding of estrogen receptor (131), and DNA-cellulose, phosphocellulose, and ADP-Sepharose binding of androgen receptor (120). In our laboratory, we have found that the inhibitor's effects on native progesterone receptor aggregates resembles, at least grossly, those of pyridoxal phosphate: it dissociates them without causing transformation, at least as monitored by in vitro DNA binding ( /.…”

“…This makes it a most interesting inhibitor, worthy of further study. An inhibition of binding of hormone to receptor has also been reported for this agent (131,132).…”

Oligodeoxynucleotide base recognition by steroid hormone receptors

“…The extent of binding to oligo(dT) followed the order: In prior experiments the mouse uterine cytosol E2R binding affinity for oligo(dG)-cellulose was the most stable after exposure to inhibitors of DNA binding [ 10,16,17]. Also binding to oligo(dT)-cellulose was usually more stable than oligo(dC)-cellulose interactions.…”

“…Testosterone was included at 1.2 pM to saturate nonestradiol binding sites. Unbound estradiol was separated from macromolecule-bound steroid with charcoal dextran as previously described [ 10,13,14]. In a parallel incubation a 200-fold excess of unlabeled estradiol was included.…”

Strong ionic interactions in noncovalent complexes between poly(ethylene imine), a cationic electrolyte, and Cibacron Blue, a nucleotide mimic – implications for oligonucleotide vectors

“…[7,8] These effects arise from the structural similarities between CB (see structure in Scheme 1) and both naturally occurring heterocycles (for example, NAD + , coenzyme A and folic acid) [8] and nucleotides. [8][9][10] CB and other anthraquinone dyes are generally called 'biomimetic dyes' or 'nucleotide-mimetic ligands' because of the specificity of their interaction with the nucleotide binding sites of several enzymes and proteins that have been shown to bind nucleotide substrates. [11,12] These types of dyes essentially mimic the structure of adenine nucleotides, such as ATP, ADP, NAD and NADH.…”