Transcriptional activation of human adult alpha-globin genes by hypersensitive site-40 enhancer: function of nuclear factor-binding motifs occupied in erythroid cells.
The developmental stage- and erythroid lineage-specific activation of the human embryonic zeta- and fetal/adult alpha-globin genes is controlled by an upstream regulatory element [hypersensitive site (HS)-40] with locus control region properties, a process mediated by multiple nuclear factor-DNA complexes. In vitro DNase I protection experiments of the two G+C-rich, adult alpha-globin promoters have revealed a number of binding sites for nuclear factors that are common to HeLa and K-562 extracts. However, genomic footprinting analysis has demonstrated that only a subset of these sites, clustered between -130 and +1, is occupied in an erythroid tissue-specific manner. The function of these in vivo-occupied motifs of the alpha-globin promoters, as well as those previously mapped in the HS-40 region, is assayed by site-directed mutagenesis and transient expression in embryonic/fetal erythroid K-562 cells. These studies, together with our expression data on the human embryonic zeta-globin promoter, provide a comprehensive view of the functional roles of individual nuclear factor-DNA complexes in the final stages of transcriptional activation of the human alpha-like globin promoters by the HS-40 element.
Rombel
I
I
Section of Molecular and Cellular Biology, University of California, Davis 95616, USA.
Hu
K Y
KY
Zhang
Q
Q
Papayannopoulou
T
T
Stamatoyannopoulos
G
G
Shen
C K
CK
D000328:Adult; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism*; D016384:Consensus Sequence; D004247:DNA / Q000097:blood / Q000737:chemistry; D017931:DNA Primers; D003850:Deoxyribonuclease I; D004622:Embryo, Mammalian; D004742:Enhancer Elements, Genetic; D004900:Erythroblasts / Q000378:metabolism*; D005333:Fetus; D005786:Gene Expression Regulation; D005914:Globins / Q000096:biosynthesis* / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
D017931:DNA Primers; D009687:Nuclear Proteins; D005914:Globins; D004247:DNA; D003850:Deoxyribonuclease I