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Erythroid‐specific activity of the glycophorin B promoter requires GATA‐1 mediated displacement of a repressor.
Author(s) -
Rahuel C.,
Vinit M.A.,
Lemarchandel V.,
Cartron J.P.,
Roméo P.H.
Publication year - 1992
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1992.tb05502.x
Subject(s) - biology , transactivation , repressor , microbiology and biotechnology , binding site , transcription factor , glycophorin , promoter , dna binding protein , transcription (linguistics) , gene , genetics , gene expression , linguistics , philosophy , antigen
We have performed a detailed analysis of the cis‐acting sequences involved in the erythroid‐specific expression of the human glycophorin B (GPB) promoter and found that this promoter could be divided into two regions. The proximal region, −1 to −60, contains a GATA binding sequence around −37 and an SP1 binding sequence around −50. This region is active in erythroid and non‐erythroid cells. The distal region, −60 to −95, contains two overlapping protein binding sites around −75, one for hGATA‐1 and one for ubiquitous proteins. This distal region completely represses the activity of the proximal promoter in non‐erythroid cells and defines the −95 GPB construct as a GPB promoter that displays erythroid specificity. Using site directed mutagenesis, we show that the −37 GATA and the −50 SP1 binding sites are necessary for efficient activity of the −95 GPB construct. Mutations that impair the −75 GATA‐1 binding result in extinction of the −95 GPB construct activity if the −75 ubiquitous binding site is not altered, or in loss of erythroid specificity if the −75 ubiquitous binding site is also mutated. Using a cotransfection assay, we found that hGATA‐1 can efficiently activate transcription of the −95 GPB construct in non‐erythroid cells. This transactivation is abolished by mutations that impair either the −37 GATA‐1 or the −50 SP1 binding. Mutations that impair the −75 GATA‐1 binding and still allow the −75 ubiquitous binding also abolish the transactivation of the −95 GPB construct, indicating that hGATA‐1 can remove repression of the GPB promoter by displacement of the ubiquitous proteins.(ABSTRACT TRUNCATED AT 250 WORDS)