title: Protection of transfective poliovirion RNA by histidine.
abstract: Transfectivity titers of RNA preparations obtained from purified poliovirions in phosphate-buffered saline using phenol were low. Addition of tissue culture nutrient medium to the virions prior to extractin with phenol increased the RNA titers 100-1000-fold. The 32 solute differences between the phosphate-buffered saline and the nutrient medium were divided into three blocs for testing. Only the bloc containing the 13 amino acids of the nutrient medium enabled the preparation of high-titer RNA. Tests of the individuals amino acids revealed that L-histidine has high activity, L-cystine and L-glutamine moderate activity, and the remaining ten zero or very slight activity. Five congeners of L-histidine, viz. D-histidine, histamine, L-histidine methyl ester, alpha-N-acetyl-L-histidine, and L-histidyl-glycine, also had high activity; but imidazole had no activity. The histidine effect was obtained whether transfection was enhanced by DEAE-dextran or by bentonite. Histidine was fully effective only when it was added to the virions before or very shortly after the phenol; later additions of histidine were progressively less effective. Without added histidine, RNA preparations made very rapidly and inoculated promptly showed high transfectivity titers, but the transfectivity was highly labile; with histidine present, the high RNA titers were stable. Histidine did not reactivate the inactivated RNA.
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D001546:Bentonite / Q000494:pharmacology; D002460:Cell Line; D006639:Histidine / Q000494:pharmacology*; D008099:Liver; D002679:Pan troglodytes; D017955:Poliovirus / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics*; D014162:Transfection / Q000187:drug effects; D014771:Virion
chemical_list: D000596:Amino Acids; D012367:RNA, Viral; D001546:Bentonite; D006639:Histidine