TY - JOUR
T1 - Cloning and characterization of the human BAG-1 gene promoter
T2 - Upregulation by tumor-derived p53 mutants
AU - Yang, Xiaolong
AU - Pater, Alan
AU - Tang, Shou Ching
N1 - Funding Information:
We thank Y Hao and G Chernenko for excellent technical assistance and Drs B Vogelstein, KH Vousden and GP Zambetti for providing mutant p53 plasmids. The investigation was supported by grants from the Medical Research Council of Canada and a grant from the National Cancer Institute of Canada with funds from the Canadian Cancer Society.
PY - 1999/8/12
Y1 - 1999/8/12
N2 - BAG-1 is an anti-apoptotic protein that interacts with Bcl-2, Bcl-X(L), Hsp70/Hsc70, Raf-1 and numerous hormone or growth factor receptors. Recently, BAG-1 has been found to be overexpressed in a variety of human cancer cell lines and some tumors. However, the molecular mechanism of BAG-1 upregulation is still unclear. In this study, we cloned 0.9 kb of human genomic DNA, BGEV, 5' flanking the BAG-1 open reading frame. BGEV subcloned into a promoterless luciferase reporter vector conferred high promoter activity in various human cancer cell lines. Deletion analysis of this sequence localized the region of maximal BAG-1 promoter activity from nucleotide positions -353 to -54, upstream of the first start codon CTG. Sequence analysis of the BAG-1 promoter region showed the absence of a TATA box but identified a CCAAT box, several GC boxes, a CpG island and several transcriptional factor binding sites, which may be important in the regulation of BAG-1 transcription. Most importantly, functional characterization of the BAG-1 promoter in vitro demonstrated that gain-of-function p53 mutants derived from human tumors upregulated the transcription of BAG-1 RNA and the expression of a reporter gene from the BAG-1 promoter. These results indicated that we have isolated the functional constitutive BAG-1 promoter. Furthermore, the data suggested that overexpression of BAG-1 in some tumors may be due to upregulation of the human BAG-1 promoter by mutant p53.
AB - BAG-1 is an anti-apoptotic protein that interacts with Bcl-2, Bcl-X(L), Hsp70/Hsc70, Raf-1 and numerous hormone or growth factor receptors. Recently, BAG-1 has been found to be overexpressed in a variety of human cancer cell lines and some tumors. However, the molecular mechanism of BAG-1 upregulation is still unclear. In this study, we cloned 0.9 kb of human genomic DNA, BGEV, 5' flanking the BAG-1 open reading frame. BGEV subcloned into a promoterless luciferase reporter vector conferred high promoter activity in various human cancer cell lines. Deletion analysis of this sequence localized the region of maximal BAG-1 promoter activity from nucleotide positions -353 to -54, upstream of the first start codon CTG. Sequence analysis of the BAG-1 promoter region showed the absence of a TATA box but identified a CCAAT box, several GC boxes, a CpG island and several transcriptional factor binding sites, which may be important in the regulation of BAG-1 transcription. Most importantly, functional characterization of the BAG-1 promoter in vitro demonstrated that gain-of-function p53 mutants derived from human tumors upregulated the transcription of BAG-1 RNA and the expression of a reporter gene from the BAG-1 promoter. These results indicated that we have isolated the functional constitutive BAG-1 promoter. Furthermore, the data suggested that overexpression of BAG-1 in some tumors may be due to upregulation of the human BAG-1 promoter by mutant p53.
KW - BAG-1
KW - Mutant p53
KW - Promoter
KW - Transactivation
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U2 - 10.1038/sj.onc.1202843
DO - 10.1038/sj.onc.1202843
M3 - Article
C2 - 10467399
AN - SCOPUS:0033549844
SN - 0950-9232
VL - 18
SP - 4546
EP - 4553
JO - Oncogene
JF - Oncogene
IS - 32
ER -
