title: Effect of L-ethionine on macromolecular synthesis in mitogen-stimulated lymphocytes.
abstract: 2--4 mM L-ethionine completely inhibits DNA synthesis in phytohaemagglutinin- or concanavalin A-stimulated lymphocytes even though it does not prevent the morphological changes characteristic of blast formation. Evidence is presented which indicates that complete commitment to DNA synthesis as well as a substantial increase in the rates of RNA and protein synthesis can occur in the presence of ethionine. Ethionine, however, does inhibit methylation of tRNA and prevents mitogen-induced increase in the activity of histone-modifying enzymes. All of these effects of exposure to ethionine are completely reversible. Removal of ethionine after 24 h or more of exposure results in a rapid, synchronous wave of DNA synthesis, an increase in the rate of methylation of RNA and an increase in activity of histone-modifying enzymes.
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D003208:Concanavalin A / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D005001:Ethionine / Q000494:pharmacology*; D006657:Histones; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D008780:Methyltransferases / Q000378:metabolism; D051379:Mice; D010835:Phytohemagglutinins / Q000494:pharmacology*; D014176:Protein Biosynthesis; D012313:RNA / Q000096:biosynthesis*
chemical_list: D006657:Histones; D010835:Phytohemagglutinins; D003208:Concanavalin A; D012313:RNA; D000255:Adenosine Triphosphate; D004247:DNA; D008780:Methyltransferases; D000123:Acetyltransferases; D005001:Ethionine