Differential expression of alpha- and beta-globin genes during differentiation of cultured erythroleukemic cells.
Murine erythroleukemic cells induced to differentiate in vitro with dimethylsulfoxide provide a model for events involved in the regulated expression of the globin genes. Here we examine alpha- and beta-globin gene expression in such cells which contain no detectable globin RNA prior to induction. To quantitate alpha- and beta-globin RNAs in cellular RNA samples by molecular hybridization techniques, highly radioactive complementary DNAs were synthesized using mouse alpha- and beta-globin RNAs purified by formamide gel electrophoresis. Maximally induced erythroleukemic cells and mouse reticulocytes contain nearly equal relative amounts of alpha- and beta-globin RNA. During the period in which globin RNA accumulates in differentiating erythroleukemic cells, however, alpha- and beta-globin RNAs are not present in equivalent amounts. alphaRNA is present in substantial excess (alpha/beta ratio 3.7) early in induction, and the alpha/beta RNA ratio progressively approaches 1 as differentiation proceeds further. These observations directly suggest that the alpha- and beta-globin genes are differentially expressed during cellular differentiation and raise questions as to how relative expression of globin genes is controlled during normal development.
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005914:Globins / Q000096:biosynthesis*; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D009691:Nucleic Acid Denaturation; D009693:Nucleic Acid Hybridization; D010944:Plants / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D012335:RNA, Ribosomal / Q000378:metabolism; D014158:Transcription, Genetic; D014908:Triticum / Q000378:metabolism
D012333:RNA, Messenger; D012335:RNA, Ribosomal; D005914:Globins; D004121:Dimethyl Sulfoxide