Changes in 3H-thymidine incorporation into the DNA by histones from normal and tumor tissues.
Attempts were made to isolate a factor from tumor tissue which, after injection, enhances the 3H-thymidine incorporation into the DNA of mice. This factor was in the cell nuclei and was extractable together with acid-soluble nuclear proteins (histones). Additional purification showed that this factor was either closely bound with the very lysine-rich histone (F1), or it was this histone itself. Acid-soluble nuclear proteins prepared from liver and thymus did not influence the incorporation of 3H-thymidine into DNA after injection. The very lysine-rich histone (F1) in these extracts was in an inactive form. It could be activated by separation from other acid-soluble nuclear proteins. Purified, the very lysine-rich histone (F1) enhanced the 3H-thymidine incorporation into DNA, regardless of its being prepared from tumor or nontumor tissues. By enhancing the incorporation of 3H-thymidine into DNA after injection, the very lysine-rich histone (F1) significantly differed from arginine-rich (F2aF3) and lysine-rich (F2b) histones which suppressed the 3H-thymidine incorporation.
Holoubek
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Cancer Research Institute, University of California Medical Center, San Francisco, California 94122, USA.
Hnilica
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LS
D000818:Animals; D001120:Arginine / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004273:DNA, Neoplasm / Q000378:metabolism*; D006657:Histones / Q000008:administration & dosage / Q000378:metabolism*; D007267:Injections; D008239:Lysine / Q000378:metabolism*; D008297:Male; D051379:Mice; D009374:Neoplasms, Experimental / Q000378:metabolism*; D013936:Thymidine / Q000378:metabolism*; D014018:Tissue Distribution; D014316:Tritium
D004273:DNA, Neoplasm; D006657:Histones; D014316:Tritium; D004247:DNA; D001120:Arginine; D008239:Lysine; D013936:Thymidine