Erythroid expression and DNAaseI-hypersensitive sites of the carbonic anhydrase 1 gene.
The carbonic anhydrase 1 gene is expressed in adult human and mouse erythroid cells and colon epithelia from two distinct promoters. We have explored the erythroid promoter for cis-acting sequences involved in transcription using DNAaseI as a probe. Two DNAaseI-hypersensitive sites (DHS-1 and DHS-2) have been identified in the distal erythroid promoter in CA1-expressing erythroleukaemic cells. These sites are present at low levels in K562 cells, which have a foetal/embryonic phenotype and do not express CA1. DHS-1 and DHS-2 are not present in non-erythroid cells, including colon cells, which express CA1 from the proximal colon promoter. DHS-1 and DHS-2 were also generated in an heterologous CA1 gene containing 5 kb of erythroid promoter sequence after transfection into erythroid cells, including K562 cells. These transfection studies showed that both this fragment, and an abbreviated 817 bp promoter fragment which contains only DHS-1, were sufficient to confer erythroid-specific expression to a reporter gene. These promoters were active in cell lines expressing CA1 and in K562 cells. This latter observation implies that a developmental repressor factor is both present in K562 cells and binds to a cis-acting sequence that is absent from the sequence 5 kb upstream of the erythroid transcription start site.
Sowden
J
J
MRC Human Biochemical Genetics Unit, Galton Laboratory (UCL), London, U.K.
Edwards
M
M
Morrison
K
K
Butterworth
P H
PH
Edwards
Y H
YH
D001483:Base Sequence; D002256:Carbonic Anhydrases / Q000235:genetics*; D002467:Cell Nucleus / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000494:pharmacology; D004912:Erythrocytes / Q000201:enzymology* / Q000502:physiology; D005786:Gene Expression Regulation; D005796:Genes; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D014162:Transfection; D014407:Tumor Cells, Cultured
D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D003850:Deoxyribonuclease I; D002256:Carbonic Anhydrases