scholarly journals Physical interaction of tumour suppressor p53/p73 with CCAAT-binding transcription factor 2 (CTF2) and differential regulation of human high-mobility group 1 (HMG1) gene expression

2003 ◽  
Vol 371 (2) ◽  
pp. 301-310 ◽  
Author(s):  
Hidetaka URAMOTO ◽  
Hiroto IZUMI ◽  
Gunji NAGATANI ◽  
Haruki OHMORI ◽  
Naofumi NAGASUE ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Replication ◽  
Dna Binding ◽  
Promoter Activity ◽  
High Mobility ◽  
Binding Activity ◽  
Physical Interaction ◽  
Dna Binding Activity ◽  
P21 Promoter ◽  
Group 1

The CCAAT-binding transcription factor (CTF)/nuclear factor I (NF-I) group of cellular DNA-binding proteins recognizes the sequence GCCAAT and is implicated in eukaryotic transcription, as well as DNA replication. Molecular analysis of human CTF/NF-I cDNA clones revealed multiple mRNA species that contain alternative coding regions, apparently as a result of differential splicing. Expression and functional analysis established that individual gene products can bind to GCCAAT recognition sites and serve as both promoter-selective transcriptional activators and initiation factors for DNA replication. The interaction between CTF2 and p53/p73 was shown to modulate their ability to regulate transcription of their respective target genes. In the present paper, we report that p53 down-regulates the activity of the high mobility group 1 (HMG1) gene promoter, whereas p73α up-regulates the activity of this promoter. Furthermore, CTF2 transactivates p53-induced p21 promoter activity, but inhibits p73α-induced p21 promoter activity. Using deletion mutants, we found that the DNA-binding domains of both p53 and p73α are required for physical interaction with CTF2 via the regions between amino acid residues 161 and 223, and 228 and 312 respectively. CTF2 enhances the DNA-binding activity of p53 and inhibits the DNA-binding activity of p73α. These results provide novel information on the functional interplay between CTF2 and p53/p73 as important determinants of their function in cell proliferation, apoptosis, DNA repair and cisplatin resistance.

scholarly journals Inherited Human XY Sex Reversal and Gonadal Neoplasia Due to Enhanced Formation of Non-Specific Enhanceosomes by an Architectural Transcription Factor

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A506-A506
Author(s):  
Yen-Shan Chen ◽  
Joseph D Racca ◽  
Alicia Belgorosky ◽  
Michael Aaron Weiss
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
High Mobility ◽  
Binding Activity ◽  
Wild Type ◽  
Cell Fates ◽  
Developmental Defects ◽  
Hmg Box ◽  
Dna Binding Activity ◽  
Gene Regulatory

Abstract The development of organisms is regulated by a fine-tuned gene-regulatory network, which is driven by transcription factors (TFs). In the embryogenesis, these TFs control diverse cell fates and final body plan. This is precisely regulated by a specific DNA-binding process and enhanceosome formation. A model is provided by testis determination in mammals, which is initiated by a Y-encoded architectural transcription factor, SRY. Mutations in SRY cause gonadal dysgenesis leading to various developmental defects. Such mutations cluster in SRY’s high mobility group (HMG) box, a sequence-specific DNA-binding domain shared by a conserved family of TFs. Here, we have characterized several mutations at the same position in HMG box, which are compatible with either male or female phenotypes as observed in an XY father and XY daughter, respectively. These mutations, at a function-unknown motif in the SRY HMG box, markedly disturb the specific DNA affinity. On transient transfection of human and rodent cell lines, the SRY variants exhibit decreased specific DNA-binding activity (relative to wild type) are associated with mis-formed enhanceosomes. The variants’ gene regulatory activities were reduced by 2-fold relative to wild-type SRY at similar levels of mRNA expression. When engineered mutations that functions to increase the DNA-binding specificity were deployed to SRY variants, the transcriptional activity was in association with restored occupancy of sex-specific enhancer elements in principal downstream gene Sox9. Our findings define a novel mechanism of impaired organogenesis, disturbed specific DNA-binding activity of a master transcription factor, leading to a developmental decision poised at the edge of ambiguity.

Ceramide decreases surfactant protein B gene expression via downregulation of TTF-1 DNA binding activity

2006 ◽  
Vol 290 (2) ◽  
pp. L351-L358 ◽  
Author(s):  
Loretta Sparkman ◽  
Hemakumar Chandru ◽  
Vijayakumar Boggaram
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Dna Binding ◽  
Promoter Activity ◽  
Surfactant Protein ◽  
Binding Activity ◽  
Mrna Levels ◽  
Dna Binding Activity ◽  
Surfactant Protein B ◽  
Tnf Α

Ceramide, a sphingolipid, is an important signaling molecule in the inflammatory response. Mediators of acute lung injury such as TNF-α, platelet-activating factor, and Fas/Apo ligand stimulate sphingomyelin hydrolysis to increase intracellular ceramide levels. Surfactant protein B (SP-B), a hydrophobic protein of pulmonary surfactant, is essential for surfactant function and lung stability. In this study we investigated the effects of ceramide on SP-B gene expression in H441 lung epithelial cells. Ceramide decreased SP-B mRNA levels in control and dexamethasone-treated cells after 24-h incubation and inhibition of SP-B mRNA was associated with inhibition of immunoreactive SP-B. In transient transfections assays, ceramide inhibited SP-B promoter activity, indicating that the inhibitory effects are exerted at the transcriptional level. Deletion mapping experiments showed that the ceramide-responsive region is located within the −233/−80-bp region of human SP-B promoter. Electrophoretic mobility shift and reporter assays showed that ceramide reduced the DNA binding activity and transactivation capability of thyroid transcription factor 1 (TTF-1/Nkx2.1), a key factor for SP-B promoter activity. Collectively these data showed that ceramide inhibits SP-B gene expression by reducing the DNA biding activity of TTF-1/Nkx2.1 transcription factor. Protein kinase C inhibitor bisindolylmaleimide and the protein tyrosine kinase inhibitor genistein partially reversed ceramide inhibition, indicating that protein kinases play important roles in the ceramide inhibition of SP-B gene expression. Chemical inhibitors of de novo ceramide synthesis and sphingomyelin hydrolysis had no effect on TNF-α inhibition of SP-B promoter activity and mRNA levels, suggesting that ceramide does not play a role in the inhibition.

A single polypeptide possesses the binding and transcription activities of the adenovirus major late transcription factor

1986 ◽  
Vol 6 (12) ◽  
pp. 4723-4733
Author(s):  
L A Chodosh ◽  
R W Carthew ◽  
P A Sharp
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Binding Site ◽  
Rna Polymerase Ii ◽  
Sodium Dodecyl ◽  
Binding Activity ◽  
Affinity Column ◽  
Dna Binding Activity ◽  
Dna Fragment

A simple approach has been developed for the unambiguous identification and purification of sequence-specific DNA-binding proteins solely on the basis of their ability to bind selectively to their target sequences. Four independent methods were used to identify the promoter-specific RNA polymerase II transcription factor MLTF as a 46-kilodalton (kDa) polypeptide. First, a 46-kDa protein was specifically cross-linked by UV irradiation to a body-labeled DNA fragment containing the MLTF binding site. Second, MLTF sedimented through glycerol gradients at a rate corresponding to a protein of native molecular weight 45,000 to 50,000. Third, a 46-kDa protein was specifically retained on a biotin-streptavidin matrix only when the DNA fragment coupled to the matrix contained the MLTF binding site. Finally, proteins from the most highly purified fraction which were eluted and renatured from the 44- to 48-kDa region of a sodium dodecyl sulfate-polyacrylamide gel exhibited both binding and transcription-stimulatory activities. The DNA-binding activity was purified 100,000-fold by chromatography through three conventional columns plus a DNA affinity column. Purified MLTF was characterized with respect to the kinetic and thermodynamic properties of DNA binding. These parameters indicate a high degree of occupancy of MLTF binding sites in vivo.

Cloning and characterization of E2F-2, a novel protein with the biochemical properties of transcription factor E2F

1993 ◽  
Vol 13 (12) ◽  
pp. 7802-7812
Author(s):  
M Ivey-Hoyle ◽  
R Conroy ◽  
H E Huber ◽  
P J Goodhart ◽  
A Oliff ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Hela Cell ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Amino Acid Identity ◽  
Biochemical Properties ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Novel Protein

E2F is a mammalian transcription factor that appears to play an important role in cell cycle regulation. While at least two proteins (E2F-1 and DP-1) with E2F-like activity have been cloned, studies from several laboratories suggest that additional homologs may exist. A novel protein with E2F-like properties, designated E2F-2, was cloned by screening a HeLa cDNA library with a DNA probe derived from the DNA binding domain of E2F-1 (K. Helin, J. A. Lees, M. Vidal, N. Dyson, E. Harlow, and A. Fattaey, Cell 70:337-350, 1992). E2F-2 exhibits overall 46% amino acid identity to E2F-1. Both the sequence and the function of the DNA and retinoblastoma gene product binding domains of E2F-1 are conserved in E2F-2. The DNA binding activity of E2F-2 is dramatically enhanced by complementation with particular sodium dodecyl sulfate-polyacrylamide gel electrophoresis-purified components of HeLa cell E2F, and anti-E2F-2 antibodies cross-react with components of purified HeLa cell E2F. These observations are consistent with a model in which E2F binds DNA as a heterodimer of two distinct proteins, and E2F-2 is functionally and immunologically related to one of these proteins.

Treatment of cultured myotubes with the proteasome inhibitor β-lactone increases the expression of the transcription factor C/EBPβ

2007 ◽  
Vol 292 (1) ◽  
pp. C216-C226 ◽  
Author(s):  
Wei Wei ◽  
Hongmei Yang ◽  
Michael Menconi ◽  
Peirang Cao ◽  
Chester E. Chamberlain ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Transcription Factor ◽  
Dna Binding ◽  
Proteasome Inhibitor ◽  
Binding Activity ◽  
Dominant Negative ◽  
Dna Binding Activity ◽  
Cultured Myotubes ◽  
Nuclear Levels ◽  
Factor C

The role of the proteasome in the regulation of cellular levels of the transcription factor CCAAT/enhancer-binding protein β (C/EBPβ) is poorly understood. We tested the hypothesis that C/EBPβ levels in cultured myotubes are regulated, at least in part, by proteasome activity. Treatment of cultured L6 myotubes, a rat skeletal muscle cell line, with the specific proteasome inhibitor β-lactone resulted in increased nuclear levels of C/EBPβ as determined by Western blotting and immunofluorescent detection. This effect of β-lactone reflected inhibited degradation of C/EBPβ. Surprisingly, the increased C/EBPβ levels in β-lactone-treated myotubes did not result in increased DNA-binding activity. In additional experiments, treatment of the myotubes with β-lactone resulted in increased nuclear levels of growth arrest DNA damage/C/EBP homologous protein (Gadd153/CHOP), a dominant-negative member of the C/EBP family that can form heterodimers with other members of the C/EBP family and block DNA binding. Coimmunoprecipitation and immunofluorescent detection provided evidence that C/EBPβ and Gadd153/CHOP interacted and colocalized in the nuclei of the β-lactone-treated myotubes. When Gadd153/CHOP expression was downregulated by transfection of myotubes with siRNA targeting Gadd153/CHOP, C/EBPβ DNA-binding activity was restored in β-lactone-treated myotubes. The results suggest that C/EBPβ is degraded by a proteasome-dependent mechanism in skeletal muscle cells and that Gadd153/CHOP can interact with C/EBPβ and block its DNA-binding activity. The observations are important because they increase the understanding of the complex regulation of the expression and activity of C/EBPβ in skeletal muscle.

scholarly journals Redox regulation of DNA binding activity of DREF (DNA replication-related element binding factor) in Drosophila

2004 ◽  
Vol 378 (3) ◽  
pp. 833-838 ◽  
Author(s):  
Tae-Yeong CHOI ◽  
S. Young PARK ◽  
Ho-Sung KANG ◽  
Jae-Hun CHEONG ◽  
Han-Do KIM ◽  
...  
Keyword(s):  
Dna Replication ◽  
Dna Binding ◽  
Redox State ◽  
Redox Regulation ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Cell Extracts ◽  
Binding Factor ◽  
Related Element ◽  
Intracellular Redox

DREF [DRE (DNA replication-related element) binding factor] is an 80 kDa polypeptide homodimer which plays an important role in regulating cell proliferation-related genes. Both DNA binding and dimer formation activities are associated with residues 16–115 of the N-terminal region. However, the mechanisms by which DREF dimerization and DNA binding are regulated remain unknown. Here, we report that the DNA binding activity of DREF is regulated by a redox mechanism, and that the cysteine residues are involved in this regulation. Electrophoretic mobility shift analysis using Drosophila Kc cell extracts or recombinant DREF proteins indicated that the DNA binding domain is sufficient for redox regulation. Site-directed mutagenesis and transient transfection assays showed that Cys59 and/or Cys62 are critical both for DNA binding and for redox regulation, whereas Cys91 is dispensable. In addition, experiments using Kc cells indicated that the DNA binding activity and function of DREF are affected by the intracellular redox state. These findings give insight into the exact nature of DREF function in the regulation of target genes by the intracellular redox state.

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