Effect of tetrahydrocortisol-apolipoprotein A-I complex on the secondary structure of eukaryotic DNA and its interaction with RNA-polymerase.
The in vitro effect of tetrahydrocortisol-apolipoprotein A-I complex on native adult rat liver DNA results in the formation of S1 nuclease sensitive fragments that are irregularly distributed throughout a genome. Low-angle X-ray scattering showed that after the interaction with the tetrahydrocortisol-apolipoprotein A-I complex, DNA can bind to RNA-polymerase with a high and dose-dependent cooperativity. This indicates that the effect of tetrahydrocortisol-apolipoprotein A-I complex on secondary eukaryotic DNA structure causes a local denaturation of the double helix, promoting high cooperativity of binding to RNA-polymerase. The reduced form of the hormone, tetrahydrocortisol, previously considered as an inactive metabolite, when complexed with apolipoprotein A-I, promotes a biological function similar to that of a transcription factor.
Research Institute of Biochemistry, Siberian Branch of the Russian Academy of Medical Sciences, Novosibirsk, 630117 Russia. ibch@cyber.ma.nsc.ru
L E
LE
Panin
O I
OI
Gimautdinova
P A
PA
Kuznetsov
M V
MV
Akimzhanova
F V
FV
Tuzikov
D000818:Animals; D016632:Apolipoprotein A-I / Q000378:metabolism / Q000494:pharmacology*; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D005057:Eukaryotic Cells; D046911:Macromolecular Substances; D009690:Nucleic Acid Conformation / Q000187:drug effects*; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013760:Tetrahydrocortisol / Q000378:metabolism / Q000494:pharmacology*
D016632:Apolipoprotein A-I; D046911:Macromolecular Substances; D013760:Tetrahydrocortisol; D004247:DNA; D012321:DNA-Directed RNA Polymerases