Analysis of the heavy metal-responsive transcription factor MTF-1 from human and mouse.
Heavy metal-induced transcription in mammalian cells is conferred by the metal-responsive 70 kDa transcription factor MTF-1 which contains six zinc fingers and at least three activation domains. In previous cell transfection experiments we have shown that the zinc finger region confers an about 3 fold metal inducibility of transcription, due to its differential zinc binding. However, we also noted that human MTF-1 was more metal-responsive than the mouse factor (about 10 fold versus 3 fold, respectively). Here we analyze this difference in more detail by using chimeric human-mouse factors and narrow the critical region to a 64 amino acid stretch immediately downstream of the zinc fingers, overlapping with the acidic activation domain. A short human segment of this region (aa 313-377) confers efficient metal induction to the mouse MTF-1 when replacing the corresponding mouse region. However, high metal inducibility requires an unaltered MTF-1 and is lost when human MTF-1 is fused to the general activation domain of herpesvirus VP16. Wild type and truncation mutants of MTF-1 fused to VP16 yield chimeras of high transcriptional activity, some exceeding the wildtype regulator, but only limited (about 3 fold) heavy metal inducibility.
Müller
H P
HP
Institut für Molekularbiologie (II) der Universität Zurich, Switzerland.
Brungnera
E
E
Georgiev
O
O
Badzong
M
M
Müller
K H
KH
Schaffner
W
W
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004268:DNA-Binding Proteins; D015870:Gene Expression / Q000187:drug effects; D006367:HeLa Cells; D017405:Herpes Simplex Virus Protein Vmw65 / Q000096:biosynthesis / Q000378:metabolism; D006801:Humans; D008322:Mammals; D008670:Metals / Q000494:pharmacology; D051379:Mice; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation; D016335:Zinc Fingers; D000097809:Transcription Factor MTF-1
D004268:DNA-Binding Proteins; D017405:Herpes Simplex Virus Protein Vmw65; D008670:Metals; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D000097809:Transcription Factor MTF-1