Early events in lymphocyte transformation by phytohemagglutinin. I. DNA-dependent RNA polymerase activities in isolated lymphocyte nuclei.
The DNA-dependent RNA polymerase activities of isolated nuclei from lymphocytes were examined after stimulation with phytohemagglutinin (PHA). The nuclear fraction was prepared with Mg(++) or Mn(++) to distinguish between polymerase I (nucleolar) and polymerase II (nucleoplasmic). Distinction between polymerases II and III was obtained by the addition of alpha-amanitin to the reaction mixture. The results indicated that within 15 min after exposure to PHA the activity of polymerase I increased. Polymerase II activity increased after 1 hr. The enhancement was linear for 6 hr and then leveled off for the subsequent 48 hr. Small increase in polymerase III activity was observed at 48 hr. Inhibition of protein synthesis at the time of exposure to PHA did not prevent the increase in activities during the initial 6 hr. These results imply that the initial increase in enzymatic activities is dependent upon preexisting polymerase molecules and/or factors.
D000255:Adenosine Triphosphate / Q000378:metabolism; D002458:Cell Fractionation; D002466:Cell Nucleolus / Q000201:enzymology; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D002794:Choline / Q000494:pharmacology; D003597:Cytosine Nucleotides / Q000378:metabolism; D004247:DNA / Q000032:analysis; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D037102:Lectins / Q000494:pharmacology*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D008274:Magnesium; D008345:Manganese; D011691:Puromycin / Q000494:pharmacology; D012313:RNA / Q000032:analysis; D012316:RNA Nucleotidyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D013997:Time Factors; D014316:Tritium; D014500:Uracil Nucleotides / Q000378:metabolism
D003597:Cytosine Nucleotides; D037102:Lectins; D014500:Uracil Nucleotides; D014316:Tritium; D008345:Manganese; D011691:Puromycin; D012313:RNA; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D004247:DNA; D012316:RNA Nucleotidyltransferases; D008274:Magnesium; D002794:Choline