Activation of the metallothionein-I gene promoter in response to cadmium and USF in vitro.
To elucidate the molecular mechanism of metallothionein (MT) gene activation in response to various inducers, we constructed a G-less mouse MT-I promoter and transcribed in HeLa nuclear extract. The MT-I gene was transcribed efficiently in this extract and initiation of transcription occurred at the correct site (+1). Transcription of the MT-I gene was stimulated three- to fivefold in the nuclear extract from the cadmium-treated cells relative to the extract from the untreated cells. The MT-I promoter was also activated three- to fourfold by recombinant USF1, a helix-loop-helix-leucine zipper DNA binding transcription factor that recognizes the major late transcription factor (MLTF) binding site on the MT-I promoter. To our knowledge, this is the first report of the activation of MT-I promoter in vitro by a toxic metal and by the transcription factor USF.
Datta
P K
PK
Department of Pharmacology and Molecular Biology, The Chicago Medical School, North Chicago, Illinois 60064, USA.
Jacob
S T
ST
D000818:Animals; D002104:Cadmium / Q000494:pharmacology*; D002467:Cell Nucleus / Q000378:metabolism; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D004268:DNA-Binding Proteins; D006367:HeLa Cells; D018257:Helix-Loop-Helix Motifs; D006801:Humans; D016350:Leucine Zippers; D008668:Metallothionein / Q000096:biosynthesis* / Q000235:genetics*; D051379:Mice; D018345:Mice, Knockout; D011401:Promoter Regions, Genetic / Q000187:drug effects; D014176:Protein Biosynthesis; D011994:Recombinant Proteins / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D051720:Upstream Stimulatory Factors
D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; C497181:USF1 protein, human; D051720:Upstream Stimulatory Factors; C497183:Usf1 protein, mouse; D002104:Cadmium; D008668:Metallothionein; D015500:Chloramphenicol O-Acetyltransferase