CACCC and GATA-1 sequences make the constitutively expressed alpha-globin gene erythroid-responsive in mouse erythroleukemia cells.
Although the human alpha-globin and beta-globin genes are co-regulated in adult life, they achieve the same end by very different mechanisms. For example, a transfected beta-globin gene is expressed in an inducible manner in mouse erythroleukemia (MEL) cells while a transfected alpha-globin gene is constitutively expressed at a high level in induced and uninduced MEL cells. Interestingly, when the alpha-globin gene is transferred into MEL cells as part of human chromosome 16, it is appropriately expressed in an inducible manner. We explored the basis for the lack of erythroid-responsiveness of the proximal regulatory elements of the human alpha-globin gene. Since the alpha-globin gene is the only functional human globin gene that lacks CACCC and GATA-1 motifs, we asked whether their addition to the alpha-globin promoter would make the gene erythroid-responsive in MEL cells. The addition of each of these binding sites to the alpha-globin promoter separately did not result in inducibility in MEL cells. However, when both sites were added together, the alpha-globin gene became inducible in MEL cells. This suggests that erythroid non-responsiveness of the alpha-globin gene results from the lack of erythroid binding sites and is not necessarily a function of the constitutively active, GC rich promoter.
Ren
S
S
Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA.
Li
J
J
Atweh
G F
GF
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000502:physiology*; D050981:Erythroid-Specific DNA-Binding Factors; D005622:Friend murine leukemia virus; D050982:GATA1 Transcription Factor; D005786:Gene Expression Regulation / Q000235:genetics*; D005914:Globins / Q000235:genetics*; D006801:Humans; D051741:Kruppel-Like Transcription Factors; D004915:Leukemia, Erythroblastic, Acute; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D014157:Transcription Factors / Q000502:physiology*; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; C494689:Gata1 protein, mouse; D051741:Kruppel-Like Transcription Factors; D014157:Transcription Factors; C080774:erythroid Kruppel-like factor; D005914:Globins