Dataset Information

Cloning, chromosomal mapping and characterization of the human metal-regulatory transcription factor MTF-1.

ABSTRACT: Metallothioneins (MTs) are small cysteine-rich proteins that bind heavy metal ions such as zinc, cadmium and copper with high affinity, and have been functionally implicated in heavy metal detoxification and radical scavenging. Transcription of metallothioneins genes is induced by exposure of cells to heavy metals. This induction is mediated by metal-responsive promoter elements (MREs). We have previously cloned the cDNA of an MRE-binding transcription factor (MTF-1) from the mouse. Here we present the human cDNA equivalent of this metal-regulatory factor. Human MTF-1 is a protein of 753 amino acids with 93% amino acid sequence identity to mouse MTF-1 and has an extension of 78 amino acids at the C-terminus without counterpart in the mouse. The factors of both species have the same overall structure including six zinc fingers in the DNA binding domain. We have physically mapped the human MTF-1 gene to human chromosome 1 where it localizes to the short arm in the region 1p32-34, most likely 1p33. Both human and mouse MTF-1 when produced in transfected mammalian cells strongly bind to a consensus MRE of metallothionein promoters. However, human MTF-1 is more effective than the mouse MTF-1 clone in mediating zinc-induced transcription.

SUBMITTER: Brugnera E

PROVIDER: S-EPMC310292 | biostudies-other | 1994 Aug

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Cloning, chromosomal mapping and characterization of the human metal-regulatory transcription factor MTF-1.

Brugnera E E Georgiev O O Radtke F F Heuchel R R Baker E E Sutherland G R GR Schaffner W W

Nucleic acids research 19940801 15

Metallothioneins (MTs) are small cysteine-rich proteins that bind heavy metal ions such as zinc, cadmium and copper with high affinity, and have been functionally implicated in heavy metal detoxification and radical scavenging. Transcription of metallothioneins genes is induced by exposure of cells to heavy metals. This induction is mediated by metal-responsive promoter elements (MREs). We have previously cloned the cDNA of an MRE-binding transcription factor (MTF-1) from the mouse. Here we pres ...[more]

PMID: 8065932

Similar Datasets

Project description:BACKGROUND: TCP proteins are plant-specific transcription factors, which are known to have a wide range of functions in different plant species such as in leaf development, flower symmetry, shoot branching, and senescence. Only a small number of TCP genes has been characterised from tomato (Solanum lycopersicum). Here we report several functional features of the members of the entire family present in the tomato genome. RESULTS: We have identified 30 Solanum lycopersicum SlTCP genes, most of which have not been described before. Phylogenetic analysis clearly distinguishes two homology classes of the SlTCP transcription factor family - class I and class II. Class II differentiates in two subclasses, the CIN-TCP subclass and the CYC/TB1 subclass, involved in leaf development and axillary shoots formation, respectively. The expression patterns of all members were determined by quantitative PCR. Several SlTCP genes, like SlTCP12, SlTCP15 and SlTCP18 are preferentially expressed in the tomato fruit, suggesting a role during fruit development or ripening. These genes are regulated by RIN (RIPENING INHIBITOR), CNR (COLORLESS NON-RIPENING) and SlAP2a (APETALA2a) proteins, which are transcription factors with key roles in ripening. With a yeast one-hybrid assay we demonstrated that RIN binds the promoter fragments of SlTCP12, SlTCP15 and SlTCP18, and that CNR binds the SlTCP18 promoter. This data strongly suggests that these class I SlTCP proteins are involved in ripening. Furthermore, we demonstrate that SlTCPs bind the promoter fragments of members of their own family, indicating that they regulate each other. Additional yeast one-hybrid studies performed with Arabidopsis transcription factors revealed binding of the promoter fragments by proteins involved in the ethylene signal transduction pathway, contributing to the idea that these SlTCP genes are involved in the ripening process. Yeast two-hybrid data shows that SlTCP proteins can form homo and heterodimers, suggesting that they act together in order to form functional protein complexes and together regulate developmental processes in tomato. CONCLUSIONS: The comprehensive analysis we performed, like phylogenetic analysis, expression studies, identification of the upstream regulators and the dimerization specificity of the tomato TCP transcription factor family provides the basis for functional studies to reveal the role of this family in tomato development.

Project description:Metal-regulatory transcription factor-1 (MTF-1) is of importance in maintaining metal homeostasis. Copper exposure considerably stimulates the proliferation of hepatocellular carcinoma (HCC) cells with enhanced MTF-1 expression. However, the underlying molecular mechanisms have not been completely elucidated. In this study, we utilized different approaches to investigate the potential role of MTF-1 involved in HCC progression. The expression levels of MTF-1 and miR-148a-3p were determined using real-time polymerase chain reaction (PCR), Western blotting, and immunohistochemistry. The interaction of MTF-1 with apurinic apyrimidinic endonuclease/redox effector factor 1 (APE/Ref-1) or miR-148a-3p was determined using immunoprecipitation or dual-luciferase reporter assay, respectively. Cell viability and metastatic ability were evaluated using colony formation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound scratch, and Transwell assays, and apoptotic cells were detected by flow cytometry. The biological functions of MTF-1 and miR-148a-3p were also determined using a xenograft mouse model. MTF-1 expression was upregulated in HCC cells and was associated with poor survival and recurrence. MTF-1 overexpression enhanced the proliferation and metastatic potential of HCC cells. Further mechanistic analyses demonstrated that MTF-1 bound to APE/Ref-1 and that MTF-1 is a direct target of miR-148-3p, which inversely regulated MTF-1 transcription activity. MiR-148a-3p overexpression effectively inhibited HCC cell proliferation and metastasis stimulated by MTF-1, with increased apoptosis. There was a decrease in miR-148a-3p expression in exosomes isolated from the plasma of patients with HCC and HCC cell culture supernatants. Co-incubation of HCC cells with exosomes from hepatocyte-conditioned media inhibited cell migration and caused apoptosis. The in vivo study revealed slow growth of MTF-1-knockdown and miR-148a-3p-overexpressing Hep3B-derived xenografts, with reduced tumor volume and weight compared with the control group. Collectively, these findings implicate MTF-1 as a modulator of HCC tumorigenesis and progression. Selective targeting towards exosomal miR-148a-3p, which might contribute to the negative regulation of MTF-1 at least partially in HCC, demonstrates therapeutic benefits for patients with HCC.

Dataset Information

Cloning, chromosomal mapping and characterization of the human metal-regulatory transcription factor MTF-1.

Publications

Cloning, chromosomal mapping and characterization of the human metal-regulatory transcription factor MTF-1.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets