[Glucocorticoid-receptor complexes of rat liver. II. Interaction with natural and synthetic polynucleotides].
The relative affinities of [3H]dexamethasone-labelled glucocorticoid-receptor complexes (GRC) from rat liver to various natural and synthetic polynucleotides differing in base composition and secondary structure have been determined. The modified competition assay procedure with use of DNA-cellulose was employed. The interaction of 150-2000 fold purified GRC with polyribo- and polydeoxyribonucleotides greatly depends on their base composition and nucleotide sequences. This interaction is hardly affected by the structure (ribo- or deoxyribo-) of the sugar-phosphate backbone or its size and is in fact independent of the secondary structure (single- or double-stranded forms) of polynucleotides. Mixtures of mononucleotides or apurinic DNA do not compete with DNA-cellulose for GRC binding. In the presence of cytosol, GRC bind double-stranded rather than single-stranded DNA, the fact possibly reflecting different effects of cytoplasmic proteins on the accessibility to GRC of polynucleotides of dissimilar secondary structure. The apparent equilibrium dissociation constants (Kd) of the ternary complexes of GRC with some synthetic polynucleotides were calculated. In case of double-stranded polydeoxyribonucleotide poly(dA) . poly(dT) Kd is equal to (1.2 +/- 0.6) x 10(-4) M; this value may characterize a nonspecific GRC--DNA interaction. It is supposed that GRC interact with high affinity (Kd approximately 10(-7)--10(-8) M) with short (5-10 nucleotides long) DNA sequences in which certain purine and pyrimidine residues are interspersed. Such DNA sequences may represent sites of primary action of GRC on the cellular genome in vivo.
D000818:Animals; D002482:Cellulose; D002846:Chromatography, Affinity; D004247:DNA; D003907:Dexamethasone / Q000378:metabolism; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D011089:Polydeoxyribonucleotides / Q000378:metabolism*; D011131:Polyribonucleotides / Q000378:metabolism*; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D013329:Structure-Activity Relationship
D011089:Polydeoxyribonucleotides; D011131:Polyribonucleotides; D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; D003907:Dexamethasone; D002482:Cellulose; D004247:DNA
Gliukokortikoid-retseptornye kompleksy pecheni krys. II. Vzaimodeĭstvie s estestvennymi i sinteticheskimi polinukleotidami.