[Effect of tetrahydrocortisol-apolipoprotein A-I complex on RNA polymerase interaction with eukaryotic DNA and the rate of protein biosynthesis in hepatocytes].
A mechanism of activation of protein biosynthesis in hepatocytes was proposed as effected by the conditioned medium of nonparenchymal liver cells incubated in the presence of high density lypoproteins, cortisol, and lypopolysaccharides. It was found that the increase in the biosynthesis rate was associated with the formation of the tetrahydrocortisol-apolipoprotein A-I (THC-apoA-I) complex in macrophages, which display 5 alpha- and 5 beta-reductase activity and are constituents of nonparenchymal liver hepatocytes. Using the small-angle X-ray scattering technique, it was shown that the THC-apoA-I-eukaryotic DNA interaction may break hydrogen bonds between pairs of complementary nucleic bases and cause the formation of single-stranded DNA fragments capable of binding to DNA-dependent RNA polymerase. The interaction is highly cooperative and has a saturating mode, up to six enzyme molecules being bound per DNA molecule.
Panin
L E
LE
Institute of Biochemistry, Siberian Division, Russian Academy of Medical Sciences, ul. Akad. Timakova 2, Novosibirsk, 630117 Russia. ibch@cyber.ma.ncs.ru
Tuzikov
F V
FV
Tuzikova
N A
NA
Usynin
I F
IF
Gimautdinova
O I
OI
D000818:Animals; D016632:Apolipoprotein A-I / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004727:Endothelium / Q000166:cytology / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism*; D006854:Hydrocortisone / Q000494:pharmacology; D007728:Kupffer Cells / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008075:Lipoproteins, HDL / Q000494:pharmacology; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D051381:Rats; D017208:Rats, Wistar; D012542:Scattering, Radiation; D013760:Tetrahydrocortisol / Q000378:metabolism* / Q000494:pharmacology; D014965:X-Rays
D016632:Apolipoprotein A-I; D008070:Lipopolysaccharides; D008075:Lipoproteins, HDL; D013760:Tetrahydrocortisol; D004247:DNA; D012321:DNA-Directed RNA Polymerases; D006854:Hydrocortisone