Regulation of ZiRF1 and basal SP1 transcription factor MRE-binding activity by transition metals.
The metal-dependent activation of metallothionein (MT) genes requires the interaction of positive trans-activators (MRFs) with metal-regulatory (MRE) regions of MT promoters. In this report, we examined the role of transition metals in modulating the MRE-binding activities of two different MRE-binding proteins: the metal-regulated factor ZiRF1 and the basal factor SP1. We showed the ability of both proteins to interact with a similar sequence specificity with the cognate target site (MRE-S) of another known MRE-binding protein, mMTF1. We next evaluated the role of metal ions in modulating the MRE-binding activity of recombinant ZiRF1 and basal SP1 proteins by measuring the effect of different metal chelators on DNA interaction. We observed a dose-dependent inhibition of the GST-ZiRF1/MRE-binding activity using three different metal chelators: EDTA, 1,10 PHE and TPEN. Interestingly, EDTA treatment failed to inhibit the recombinant SP1 MRE-binding activity while the effect of 1,10 PHE was comparable to that obtained analyzing 1,10 PHE-treated GST-ZiRF1. The MRE-binding complexes detected in cell extracts showed a response to metal chelator treatment very similar to that displayed by the recombinant ZiRF1 and SP1 proteins. The hypothesis of mutual interactions of both basal and metal-regulated transcription factors with the same metal-regulatory regions is discussed.
Remondelli
P
P
Dipartimento di Biochimica e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Naples, Italy. remondel@unina.it
Moltedo
O
O
Leone
A
A
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D004492:Edetic Acid / Q000494:pharmacology; D005029:Ethylenediamines / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects*; D005982:Glutathione Transferase; D007739:L Cells; D008668:Metallothionein / Q000096:biosynthesis* / Q000235:genetics; D008670:Metals / Q000494:pharmacology*; D051379:Mice; D009838:Oligodeoxyribonucleotides; D010618:Phenanthrolines / Q000494:pharmacology; D011033:Podophyllin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D011034:Podophyllotoxin / Q000031:analogs & derivatives; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014162:Transfection; D000097809:Transcription Factor MTF-1
D002614:Chelating Agents; D004268:DNA-Binding Proteins; D004492:Edetic Acid; D005029:Ethylenediamines; D005982:Glutathione Transferase; D008668:Metallothionein; D008670:Metals; D009838:Oligodeoxyribonucleotides; D010618:Phenanthrolines; D011033:Podophyllin; D011034:Podophyllotoxin; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D000097809:Transcription Factor MTF-1; C003170:mitopodozide; C044387:N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine; C025205:1,10-phenanthroline