title: Localization of globin gene replication in Friend Leukemia cells to a specific interval of the S phase.
abstract: Murine erythroblastic leukemia cells, infected with Friend leukemia virus, were grown and synchronized in suspension culture by a double-block procedure involving medium depletion and treatment with excess thymidine. Replicating cultures were then caused to synthesize DNA during the early, middle, or late third of the S period with bromodeoxyuridine as a precursor. The bromodeoxyuridine density-labeled DNA and normal DNA were isolated by sedimentation in a cesium chloride density gradient and analyzed for the level of globin-specific DNA by hybridization with radioactive cDNA of the globin messenger RNA. Globin genes were found to be replicated near the end of the middle third of the S phase. The incorporation of bromodeoxyuridine into DNA also resulted in a lowered induction of hemoglobin synthesis in dimethyl sulfoxide-treated cells. In this case, the sensitivity was correlated with the introduction of bromodeoxyuridine into DNA replicated in early S phase. The possibility that this fraction of DNA, which is low in globin gene content, carries genes regulating the erythroid differentiation or the expression of globin genes is discussed.
mesh_terms: D000818:Animals; D001973:Bromodeoxyuridine / Q000494:pharmacology; D002453:Cell Cycle; D002460:Cell Line; D004261:DNA Replication / Q000187:drug effects; D004273:DNA, Neoplasm / Q000096:biosynthesis*; D005796:Genes; D005914:Globins / Q000096:biosynthesis*; D006454:Hemoglobins / Q000096:biosynthesis; D007399:Interphase; D007942:Leukemia, Experimental / Q000378:metabolism*; D051379:Mice; D013936:Thymidine / Q000378:metabolism
chemical_list: D004273:DNA, Neoplasm; D006454:Hemoglobins; D005914:Globins; D001973:Bromodeoxyuridine; D013936:Thymidine