Erythroid AP-1/NF-E2 elements vary in their response to NF-E2.
AP-1/NF-E2 motifs found in erythroid transcription control elements are associated with powerful transcription activation and thought to be regulated by the erythroid transcription factor NF-E2. We have studied AP-1/NF-E2 motifs from three different erythroid control elements (5'HS2 of the human beta-globin locus control region [LCR], the porphobilinogen deaminase [PBGD] promoter, and the mouse Band 3 promoter). We find that these AP-1/NF-E2 elements differ both in their ability to bind NF-E2 and their activity in transient assays. Each of the elements is bound by AP-1, but only the 5'HS2 and PBGD sites are bound by NF-E2. We examined the activity of these sites in minimal promoter constructs in transient assays. In erythroid cells, activity of duplicated NF-E2 motifs is positively correlated with binding by NF-E2; however, the Band 3 element not bound by NF-E2 is also active in some contexts. In HeLa cells, all sites were active and duplicated sites were most active. In F9 mouse teratocarcinoma cells, which express neither NF-E2 nor AP-1, the elements' activity parallels that in erythroid cells. While these finding are consistent with other evidence that NF-E2 is an important regulator of erythroid transcription, they suggest that some sites that resemble NF-E2 elements are actually regulated by other factors; we speculate that other tissue-specific and/or generally expressed factors may act on these sites.
Walters
M
M
Division of Clinical Research, Fred Hutchinson Cancer Research Center, Seattle, WA USA.
Andrews
N C
NC
Magis
W
W
Martin
D I
DI
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000494:pharmacology*; D050981:Erythroid-Specific DNA-Binding Factors; D005914:Globins / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D004915:Leukemia, Erythroblastic, Acute; D051379:Mice; D008969:Molecular Sequence Data; D050983:NF-E2 Transcription Factor; D050984:NF-E2 Transcription Factor, p45 Subunit; D011401:Promoter Regions, Genetic; D011817:Rabbits; D012045:Regulatory Sequences, Nucleic Acid; D018808:Transcription Factor AP-1 / Q000378:metabolism / Q000494:pharmacology*; D014157:Transcription Factors / Q000378:metabolism / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050983:NF-E2 Transcription Factor; D050984:NF-E2 Transcription Factor, p45 Subunit; C494692:NFE2 protein, human; C494693:Nfe2 protein, mouse; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D005914:Globins; D004247:DNA