Effect of dexamethasone on nuclear envelope nucleoside triphosphatase in fibroblasts 3T3 and melanoma cells MMLI.
Glucocorticoids are known to influence DNA and RNA synthesis in skin fibroblasts. In a novel approach to study this effect, we investigated the influence of the hormone analogue dexamethasone on the activity of nuclear envelope-associated nucleoside triphosphatase (NTPase) in intact cell systems (3T3 fibroblasts and MMLI melanoma cells). The NTPase is thought to be responsible for regulation of nucleocytoplasmic transport of mRNA. [3H]Dexamethasone was found to bind to nuclear ghosts at a density comparable with that of nuclear pores in this cellular fraction. Incubation of the cells for 48 h in the presence of different concentrations of dexamethasone resulted in a marked decrease of NTPase activity. Already concentrations as low as 0.1 ng/ml (3T3) or 1 ng/ml (MMLI) reduced the NTPase activity by approximately 50%. These results suggest that nuclear envelope NTPase is a site at which glucocorticoids regulate gene expression.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D003907:Dexamethasone / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D008545:Melanoma / Q000201:enzymology*; D051379:Mice; D009685:Nuclear Envelope / Q000187:drug effects* / Q000201:enzymology; D043583:Nucleoside-Triphosphatase; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012334:RNA, Neoplasm / Q000378:metabolism; D013997:Time Factors
D012333:RNA, Messenger; D012334:RNA, Neoplasm; D003907:Dexamethasone; D010744:Phosphoric Monoester Hydrolases; D043583:Nucleoside-Triphosphatase