Search results for "DNA-Directed DNA Polymerase"
showing 4 items of 24 documents
Alterations of DNA-dependent DNA polymerase activities in the immature quail oviduct in response to estrogen stimulation.
1975
Administration of diethylstilbestrol, an estrogen analogue, to immature female quails causes an increase of extractable DNA-dependent DNA polymerase activities from the oviduct. At least two forms of polymerases have been determined, a high molecular weight polymerase (210,000 daltons) and a low molecular weight polymerase (34,000 daltons) calculated from column chromatography Sephadex G-200. During the primary hormone stimulation the amount of extractable enzyme reaches a maximum on the fifth day after daily injections of the hormone. In the period of withdrawal the activities decrease and reach values similar to those determined in the unstimulated oviducts. During secondary stimulation t…
Biochemical Aspects of Chick Embryo Retina Development: The Effects of Glucocorticoids
1989
In chick embryo retina during development, DNA synthesis and the activities of DNA polymerase, thymidine kinase, thymidylate synthetase, and ornithine decarboxylase (ODC) declined in parallel from day 7 to 12. The administration in ovo of hydrocortisone reduced significantly, particularly at 8-10 days of incubation, both DNA synthesis and the four enzyme activities tested. The effect was dose dependent, reaching the maximum with 50-100 nmol of hydrocortisone, 8-16 h after treatment. The highest inhibition was found for ODC activity (70%), followed by thymidine kinase activity (62%) and DNA synthesis (45%), whereas activities of DNA polymerase and thymidylate synthetase were reduced only by …
Poly(adenosine diphosphate-ribose) polymerase in quail oviduct. Changes during estrogen and progesterone induction
1974
Abstract The activities of the following enzymes have been determined in nuclei of quail oviducts in response to exogenous stimulation of the birds with diethylstilbestrol, used as an estrogen analogue and progesterone: DNA dependent DNA polymerase, DNA dependent RNA polymerase I and II and poly(adenosine diphosphate-ribose) [=poly(ADP-Rib)] polymerase. During primary stimulation with the estrogen analogue the activities of the four DNA dependent polymerases increase to about the same degree. Upon withdrawal of the hormones the levels of the enzymes drop to values known from nuclei from unstimulated quail oviducts. The secondary stimulation with the estrogen analogue causes a significant in…
Influence of aryl hydrocarbon- (Ah) receptor and genotoxins on DNA repair gene expression and cell survival of mouse hepatoma cells
2009
The aryl hydrocarbon receptor (AhR) mediates toxicity of a variety of environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs) and dioxins. However, the underlying mechanisms and genetic programmes regulated by AhR to cause adverse effects but also to counteract poisoning are still poorly understood. Here we analysed the effects of two AhR ligands, benzo[a]pyrene (B[a]P), a DNA damaging tumour initiator and promotor and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a pure tumour promoter, on cell survival and on nucleotide excision repair (NER) gene expression. NER deals with so called "bulky" DNA adducts including those generated by enzymatically activated B[a]P. Therefore, t…