title: Induction of ornithine decarboxylase by transcriptional inhibitors in quiescent thymocytes.
abstract: The transcriptional inhibitors actinomycin D and dichlororibofuranosylbenzimidazole induced ornithine decarboxylase activity in isolated, quiescent thymocytes, which otherwise did not show detectable levels of the enzyme. This paradoxical induction was transient and dependent on the presence of serum and continuous protein synthesis. However, alpha-amanitin, another inhibitor of transcription, did not affect ornithine decarboxylase activity. Dichlororibofuranosylbenzimidazole and actinomycin D were unable to enhance the activity of spermidine acetyltransferase or S-adenosyl-methionine decarboxylase, which are other inducible and short-lived enzymes involved in the metabolism of polyamines.
authors.affiliation: Department of Biochemistry, G. Moruzzi, University of Bologna, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Stefanelli
authors.forename: F
authors.initials: F
authors.lastname: Flamigni
authors.forename: F
authors.initials: F
authors.lastname: Ferrari
authors.forename: C
authors.initials: C
authors.lastname: Rossoni
authors.forename: C M
authors.initials: CM
authors.lastname: Caldarera
mesh_terms: D000818:Animals; D003609:Dactinomycin / Q000494:pharmacology; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology; D004790:Enzyme Induction / Q000187:drug effects; D066298:In Vitro Techniques; D007399:Interphase; D008297:Male; D009955:Ornithine Decarboxylase / Q000096:biosynthesis*; D011073:Polyamines / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D011073:Polyamines; D003609:Dactinomycin; D004004:Dichlororibofuranosylbenzimidazole; D009955:Ornithine Decarboxylase