METAL-DEPENDENT BINDING OF A NUCLEAR FACTOR TO THE RAT METALLOTHIONEIN-I PROMOTER

被引:48
作者
ANDERSEN, RD [1 ]
TAPLITZ, SJ [1 ]
OBERBAUER, AM [1 ]
CALAME, KL [1 ]
HERSCHMAN, HR [1 ]
机构
[1] UNIV CALIF LOS ANGELES,DEPT BIOL CHEM,LOS ANGELES,CA 90024
关键词
D O I
10.1093/nar/18.20.6049
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Genomic footprintlng studies in vivo and experiments using synthetic metal regulatory elements (MREs) in vitro suggest protein binding to the MREs of the mouse and rat metallothionein I (MT-I) genes. Using gel-retardation assays of promoter fragments, we observe a cadmium-dependent binding factor for the rat MT-I promoter in rat hepatoma cells . This factor is present in extracts from both uninduced and cadmium-induced cells, but requires the presence of cadmium to bind to the promoter. The formation of a cadmium-dependent complex is competed by an oligonucleotide containing two MREs. This competition is lost when when one of the MREs is mutated, Indicating a requirement for atleast two MREs for binding of this factor. The cadmium-dependent factor dissociates more rapidly from the MT-I promoter than does a factor that binds to a consensus Sp1 site present on the same DNA fragment. UV crosslinking analysis using nuclear extracts from cadmium induced cells, In the presence of an oligonucleotide probe containing both 5-bromodeoxyurldine and 32P-deoxycytidine, identifies a 39 kDalton protein associated with the metal inducible complex. © 1990 Oxford University Press.
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页码:6049 / 6055
页数:7
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