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Sp1/AP2‐dependent regulation of the TATA‐less promoter of the CMP‐NeuAc:GM3 2,8 sialyltransferase (GD3‐synthase) gene
Author(s) -
Zeng Guichao,
Gao Luoyi,
Gu Yihua,
Sun Xutong,
Xia Tian,
Yu Robert K.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.782.3
Subject(s) - transactivation , microbiology and biotechnology , repressor , promoter , binding site , biology , gene , cell culture , activator (genetics) , transcription factor , chemistry , gene expression , biochemistry , genetics
Expression of the GD3‐synthase (GD3S) gene is cell type‐specific. To confer cell type‐specific regulation, we assayed the proximal promoter (525 bp) activity of the gene in rat F‐11 and PC12 cells, which express high or low levels of GD3S, respectively. The promoter activity in PC12 cells was ~13% of that in F‐11 cells. The function of the regulatory elements was analyzed by deletion or mutation of the sites. The Sp1‐Sp1 site at −428 was essential for the promoter activation in both F‐11 and PC12 cells, and deletion or mutation of GATA, Ets‐1, AP1 and NFkB sites had no effects on the activity in both cell lines. However, the Sp1 site at −309 was required for the promoter activity in PC12 cells but not in F‐11 cells. The AP2‐binding site at −329 and −140 functioned as an activator in the Sp1‐mediated transactivation in F‐11 cells, while as a repressor in PC12 cells. ChIP assays revealed that AP2 and Sp1 bound to the AP2‐binding site at −140 and the Sp1‐Sp1 site at −428, respectively, in both cell lines, but AP2 bound to the AP2 site at −329 only in F‐11 cells and Sp1 bound to its site at −309 only in PC12 cells, presenting in vivo cell type‐specific interactions between TFs and DNA elements. Sp3 has no effect on the promoter activity. Overexpression of Sp1 increased the promoter activity by 2‐fold in F‐11 cells, but not in PC12 cells. Our data indicate that cell type‐specific regulation of the GD3S gene is Sp1/AP2‐dependent. Supported by NIH NS11853