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PROMOTERS FOR THE HUMAN ALCOHOL-DEHYDROGENASE GENES ADH1, ADH2, AND ADH3 - INTERACTION OF CCAAT/ENHANCER-BINDING PROTEIN WITH ELEMENTS FLANKING THE ADH2 TATA BOX
被引:37
作者:
STEWART, MJ
[1
]
MCBRIDE, MS
[1
]
WINTER, LA
[1
]
DUESTER, G
[1
]
机构:
[1] COLORADO STATE UNIV,DEPT BIOCHEM,FT COLLINS,CO 80523
来源:
关键词:
DNase I footprinting;
Gene expression;
gene family;
recombinant DNA;
transcription factors;
D O I:
10.1016/0378-1119(90)90190-3
中图分类号:
Q3 [遗传学];
学科分类号:
071007 ;
090102 ;
摘要:
The human ADH1, ADH2, and ADH3 genes are closely related members of a gene family which are differentially expressed during liver development. To begin examining the mechanism of this tissue-specific and stage-specific expression, the 5′-flanking nucleotide (nt) sequences of the three genes were determined and the transcription start points (tsp) were identified. Sequences of all three genes indicated a high degree of homology (>80% nt sequence identity) from the AUG translation start codon to about nt -780 relative to the tsp. Transiwnt transfection assays of a set of plasmids containing various lengths of ADH 5′-flanking DNA fused to cat were performed in the HepG2 and Hep3B human hepatoma cell lines. The results indicated that the ADH2 promoter-proximal region was transcriptionally active in the absence of upstream sequences. To identify potential cis-acting elements in the ADH2 promoter-proximal region, a DNase I footprinting assay using a rat liver nuclear extract was used. Protection occurred in several locations including one, between nt -51 and -10, which shares homology with known binding sites for a previously identified rat-liver transcription factor called CCAAT/enhancer binding protein (C/EBP). Purified C/EBP was shown by footprint analysis to bind at two distinct sites in the ADH2 promoter located at nt -51 to -31 and -21 to -10. The TATA-box promoter element at nt -30 to -22 was not protected by C/EBP, but was partially protected by a factor in the rat liver nuclear extract. Thus, it is possible that the flanking C/EBP molecules may create a novel binding pocket for TFIID, the TATA-binding general transcription factor for RNA polymerase II. Alternatively, the C/EBP molecules may block access to the TATA box, and stimulate transcription of ADH2 by interacting with some component(s) other than TFIID. © 1990.
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页码:271 / 279
页数:9
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