scholarly journals Identification of the varR Gene as a Transcriptional Regulator of Virginiamycin S Resistance inStreptomyces virginiae

2001 ◽  
Vol 183 (6) ◽  
pp. 2025-2031 ◽  
Author(s):  
Wises Namwat ◽  
Chang-Kwon Lee ◽  
Hiroshi Kinoshita ◽  
Yasuhiro Yamada ◽  
Takuya Nihira
Keyword(s):  
Dna Binding ◽  
Promoter Region ◽  
Northern Blot Analysis ◽  
Binding Activity ◽  
Binding Motif ◽  
Dependent Manner ◽  
Gene Encoding ◽  
Dna Binding Activity ◽  
Streptomyces Virginiae

ABSTRACT A gene designated varR (for virginiaeantibiotic resistance regulator) was identified in Streptomyces virginiae 89 bp downstream of a varS gene encoding a virginiamycin S (VS)-specific transporter. The deduced varRproduct showed high homology to repressors of the TetR family with a conserved helix-turn-helix DNA binding motif. Purified recombinant VarR protein was present as a dimer in vitro and showed clear DNA binding activity toward the varS promoter region. This binding was abolished by the presence of VS, suggesting that VarR regulates transcription of varS in a VS-dependent manner. Northern blot analysis revealed that varR was cotranscribed with upstream varS as a 2.4-kb transcript and that VS acted as an inducer of bicistronic transcription. Deletion analysis of thevarS promoter region clarified two adjacent VarR binding sites in the varS promoter.

scholarly journals CP-31398 Restores DNA-binding Activity to Mutant p53in Vitrobut Does Not Affect p53 Homologs p63 and p73

2004 ◽  
Vol 279 (44) ◽  
pp. 45887-45896 ◽  
Author(s):  
Mark J. Demma ◽  
Serena Wong ◽  
Eugene Maxwell ◽  
Bimalendu Dasmahapatra
Keyword(s):  
Dna Binding ◽  
Mammalian Cells ◽  
P53 Protein ◽  
Binding Activity ◽  
Mutant P53 ◽  
Dependent Manner ◽  
Wild Type ◽  
Dna Binding Activity

The p53 protein plays a major role in the maintenance of genome stability in mammalian cells. Mutations of p53 occur in over 50% of all cancers and are indicative of highly aggressive cancers that are hard to treat. Recently, there has been a high degree of interest in therapeutic approaches to restore growth suppression functions to mutant p53. Several compounds have been reported to restore wild type function to mutant p53. One such compound, CP-31398, has been shown effectivein vivo, but questions have arisen to whether it actually affects p53. Here we show that mutant p53, isolated from cells treated with CP-31398, is capable of binding to p53 response elementsin vitro. We also show the compound restores DNA-binding activity to mutant p53 in cells as determined by a chromatin immunoprecipitation assay. In addition, using purified p53 core domain from two different hotspot mutants (R273H and R249S), we show that CP-31398 can restore DNA-binding activity in a dose-dependent manner. Using a quantitative DNA binding assay, we also show that CP-31398 increases significantly the amount of mutant p53 that binds to cognate DNA (Bmax) and its affinity (Kd) for DNA. The compound, however, does not affect the affinity (Kdvalue) of wild type p53 for DNA and only increasesBmaxslightly. In a similar assay PRIMA1 does not have any effect on p53 core DNA-binding activity. We also show that CP-31398 had no effect on the DNA-binding activity of p53 homologs p63 and p73.

scholarly journals Retinoid-induced apoptosis and Sp1 cleavage occur independently of transcription and require caspase activation.

1997 ◽  
Vol 17 (11) ◽  
pp. 6348-6358 ◽  
Author(s):  
F J Piedrafita ◽  
M Pfahl
Keyword(s):  
T Cells ◽  
Dna Binding ◽  
Cancer Cell ◽  
De Novo ◽  
Binding Activity ◽  
Dependent Manner ◽  
Intact Cells ◽  
Dna Binding Activity ◽  
Induced Apoptosis

Vitamin A and its derivatives, the retinoids, are essential regulators of many important biological functions, including cell growth and differentiation, development, homeostasis, and carcinogenesis. Natural retinoids such as all-trans retinoic acid can induce cell differentiation and inhibit growth of certain cancer cells. We recently identified a novel class of synthetic retinoids with strong anti-cancer cell activities in vitro and in vivo which can induce apoptosis in several cancer cell lines. Using an electrophoretic mobility shift assay, we analyzed the DNA binding activity of several transcription factors in T cells treated with apoptotic retinoids. We found that the DNA binding activity of the general transcription factor Sp1 is lost in retinoid-treated T cells undergoing apoptosis. A truncated Sp1 protein is detected by immunoblot analysis, and cytosolic protein extracts prepared from apoptotic cells contain a protease activity which specifically cleaves purified Sp1 in vitro. This proteolysis of Sp1 can be inhibited by N-ethylmaleimide and iodoacetamide, indicating that a cysteine protease mediates cleavage of Sp1. Furthermore, inhibition of Sp1 cleavage by ZVAD-fmk and ZDEVD-fmk suggests that caspases are directly involved in this event. In fact, caspases 2 and 3 are activated in T cells after treatment with apoptotic retinoids. The peptide inhibitors also blocked retinoid-induced apoptosis, as well as processing of caspases and proteolysis of Sp1 and poly(ADP-ribose) polymerase in intact cells. Degradation of Sp1 occurs early during apoptosis and is therefore likely to have profound effects on the basal transcription status of the cell. Interestingly, retinoid-induced apoptosis does not require de novo mRNA and protein synthesis, suggesting that a novel mechanism of retinoid signaling is involved, triggering cell death in a transcriptional activation-independent, caspase-dependent manner.

Characterization of the mouse metal-regulatory-element-binding proteins, metal element protein-1 and metal regulatory transcription factor-1

2001 ◽  
Vol 353 (3) ◽  
pp. 591-601 ◽  
Author(s):  
Olivier LAROCHELLE ◽  
Gale STEWART ◽  
Pierre MOFFATT ◽  
Véronique TREMBLAY ◽  
Carl SÉGUIN
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Binding Activity ◽  
Dependent Manner ◽  
Rnase Protection ◽  
Dna Binding Activity ◽  
Cell Extracts ◽  
Metal Element ◽  
Transcription Factor 1

Metal activation of metallothionein gene transcription depends mainly on the presence of regulatory DNA sequences termed metal-regulatory elements (MREs) and involves MRE-binding transcription factor-1 (MTF-1) interacting with the MREs in a Zn2+-dependent manner. We previously identified and characterized a nuclear protein, termed metal element protein-1 (MEP-1), specifically binding with high affinity to MRE elements. The precise relationship between MTF-1 and MEP-1 was unclear, and to determine whether MEP-1 and MTF-1 were distinct protein species, we performed DNA binding analyses to characterize the binding properties of both proteins. Electrophoretic mobility-shift assays showed that MTF-1, produced in COS cells, produces a slower-migrating band compared with that obtained with purified MEP-1. Using an anti-MTF-1 antibody, we showed that both the MTF-1–MRE and the MEP-1–MRE complexes are supershifted by an anti-MTF-1 antibody, thus demonstrating that MEP-1 is antigenically related to MTF-1. RNase protection analyses carried out with RNA prepared from different tissues and cell lines failed to reveal the presence of MTF-1 splicing variants. This indicates that MEP-1 may be a proteolytic fragment of MTF-1. MTF-1 DNA-binding activity was rapidly activated in vivo by Zn2+ ions but not by Cd2+, UV irradiation or PMA, and occurred on ice as well as at 21°C. In control and Zn2+-treated cell extracts, DNA-binding activity was not enhanced in vitro following the addition of exogenous Zn2+ or a preincubation at 37°C. However, recombinant MTF-1 produced in vitro required Zn2+ activation for DNA binding. Interestingly, treatment of nuclear extracts with calf intestine phosphatase completely abrogated MTF-1 DNA-binding activity, thus suggesting that phosphorylation is involved in the regulation of MTF-1 activity.

scholarly journals A Novel PF/PN Motif Inhibits Nuclear Localization and DNA Binding Activity of the ESX1 Homeoprotein

2000 ◽  
Vol 20 (2) ◽  
pp. 661-671 ◽  
Author(s):  
Yu-Ting Yan ◽  
Stacey M. Stein ◽  
Jixiang Ding ◽  
Michael M. Shen ◽  
Cory Abate-Shen
Keyword(s):  
Dna Binding ◽  
Subcellular Localization ◽  
Nuclear Localization ◽  
Molecular Mechanisms ◽  
Binding Activity ◽  
Binding Motif ◽  
Rich Region ◽  
Dna Binding Activity ◽  
Proline Rich Region

ABSTRACT Despite their significance for mammalian embryogenesis, the molecular mechanisms that regulate placental growth and development have not been well defined. The Esx1 homeobox gene is of particular interest because it is among the few regulatory genes that have specific expression and function in the placenta during murine development. In addition, the ESX1 protein contains several notable features that are not often associated with homeoproteins, including an atypical homeodomain of the paired-like class, a proline-rich region that contains an SH3 binding motif, and a novel repeat region consisting of prolines alternating with phenylalanines or asparagines that we term the PF/PN motif. We have found that the ESX1 protein is expressed in the labyrinth layer of the placenta in vivo, where its subcellular localization is primarily cytoplasmic. Our results suggest that this unexpected subcellular localization is conferred by the PF/PN motif, which inhibits nuclear localization of ESX1 in cell culture, as well as its DNA binding activity in vitro. Finally, we show that the proline-rich region of ESX1 mediates interactions in vitro with the c-abl SH3 domain as well as with certain WW domains. We propose that the PF/PN motif provides a novel mechanism for regulating nuclear entry and that the essential function of ESX1 during placental development is mediated by its ability to couple cytoplasmic signal transduction events with transcriptional regulation in the nucleus.

scholarly journals Chlorogenic Acid Inhibits BAFF Expression in Collagen-Induced Arthritis and Human Synoviocyte MH7A Cells by Modulating the Activation of the NF-κB Signaling Pathway

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Xiaohong Fu ◽  
Xilin Lyu ◽  
Han Liu ◽  
Dan Zhong ◽  
Zhizhen Xu ◽  
...  
Keyword(s):  
Dna Binding ◽  
Chlorogenic Acid ◽  
Promoter Region ◽  
Critical Role ◽  
Binding Activity ◽  
Dependent Manner ◽  
Collagen Induced Arthritis ◽  
Dna Binding Activity ◽  
Dna Binding Site ◽  
Dose Dependent

B cell activating factor (BAFF), a member of the tumor necrosis factor (TNF) family, plays a critical role in the pathogenesis and progression of rheumatoid arthritis (RA). Chlorogenic acid (CGA) is a phenolic compound and exerts antiarthritic activities in arthritis. However, it is not clear whether the anti-inflammatory property of CGA is associated with the regulation of BAFF expression. In this study, we found that treatment of the collagen-induced arthritis (CIA) mice with CGA significantly attenuated arthritis progression and markedly inhibited BAFF production in serum as well as the production of serum TNF-α. Furthermore, CGA inhibits TNF-α-induced BAFF expression in a dose-dependent manner and apoptosis in MH7A cells. Mechanistically, we found the DNA-binding site for the transcription factor NF-κB in the BAFF promoter region is required for this regulation. Moreover, CGA reduces the DNA-binding activity of NF-κB to the BAFF promoter region and suppresses BAFF expression through the NF-κB pathway in TNF-α-stimulated MH7A cells. These results suggest that CGA may serve as a novel therapeutic agent for the treatment of RA by targeting BAFF.

Differential use of SCL/TAL-1 DNA-binding domain in developmental hematopoiesis

Blood ◽  
2008 ◽  
Vol 112 (4) ◽  
pp. 1056-1067 ◽  
Author(s):  
Mira T. Kassouf ◽  
Hedia Chagraoui ◽  
Paresh Vyas ◽  
Catherine Porcher
Keyword(s):  
Dna Binding ◽  
Molecular Mechanisms ◽  
Binding Activity ◽  
Hematopoietic Stem ◽  
Helix Loop Helix ◽  
Experimental Systems ◽  
Dna Binding Activity ◽  
Independent Functions

Abstract Dissecting the molecular mechanisms used by developmental regulators is essential to understand tissue specification/differentiation. SCL/TAL-1 is a basic helix-loop-helix transcription factor absolutely critical for hematopoietic stem/progenitor cell specification and lineage maturation. Using in vitro and forced expression experimental systems, we previously suggested that SCL might have DNA-binding–independent functions. Here, to assess the requirements for SCL DNA-binding activity in vivo, we examined hematopoietic development in mice carrying a germline DNA-binding mutation. Remarkably, in contrast to complete absence of hematopoiesis and early lethality in scl-null embryos, specification of hematopoietic cells occurred in homozygous mutant embryos, indicating that direct DNA binding is dispensable for this process. Lethality was forestalled to later in development, although some mice survived to adulthood. Anemia was documented throughout development and in adulthood. Cellular and molecular studies showed requirements for SCL direct DNA binding in red cell maturation and indicated that scl expression is positively autoregulated in terminally differentiating erythroid cells. Thus, different mechanisms of SCL's action predominate depending on the developmental/cellular context: indirect DNA binding activities and/or sequestration of other nuclear regulators are sufficient in specification processes, whereas direct DNA binding functions with transcriptional autoregulation are critically required in terminal maturation processes.

Extinction of insulin gene expression in hybrids between beta cells and fibroblasts is accompanied by loss of the putative beta-cell-specific transcription factor IEF1

1991 ◽  
Vol 11 (3) ◽  
pp. 1547-1552
Author(s):  
D Leshkowitz ◽  
M D Walker
Keyword(s):  
Gene Expression ◽  
Dna Binding ◽  
Binding Activity ◽  
Insulin Gene ◽  
Hybrid Cells ◽  
Dna Binding Activity ◽  
Insulin Producing Cells ◽  
Insulin Gene Expression ◽  
Insulinoma Cells

Insulin-producing cells and fibroblasts were fused to produce hybrid lines. In hybrids derived from both hamster and rat insulinoma cells, no insulin mRNA could be detected in any of seven lines examined by Northern (RNA) analysis despite the presence in each line of the insulin genes of both parental cells. Hybrid cells were transfected with recombinant chloramphenicol acetyltransferase plasmids containing defined segments of the rat insulin I gene 5' flank. We observed no transcriptional activity of the intact insulin enhancer or of IEB2, a critical cis-acting element of the insulin enhancer. IEB2 has previously been shown to interact in vitro with IEF1, a DNA-binding activity observed selectively in insulin-producing cells. Hybrid cells showed no detectable IEF1 activity. Furthermore, the insulin enhancer was unable to reduce transcription directed by the Moloney sarcoma virus enhancer in a double-enhancer construct. Thus, extinction of insulin gene expression in the hybrids apparently does not operate through a direct action of repressors on the insulin enhancer; rather, extinction is accompanied by, and may be caused by, reduced DNA-binding activity of the putative transcriptional activator IEF1.

Identification of a 150-kilodalton polypeptide that copurifies with yeast TFIIIC and binds specifically to tRNA genes

1989 ◽  
Vol 9 (5) ◽  
pp. 2018-2024
Author(s):  
D L Johnson ◽  
S L Wilson
Keyword(s):  
Dna Binding ◽  
Rna Polymerase Iii ◽  
Deae Cellulose ◽  
Binding Activity ◽  
Trna Genes ◽  
Dna Binding Activity ◽  
Transcription In Vitro ◽  
Affinity Interaction ◽  
Dna Complex

The transcription in vitro of eucaryotic tRNA genes by RNA polymerase III requires two transcription factors, designated TFIIIB and TFIIIC. One of the critical functions of TFIIIC in the transcription of tRNA genes is that it interacts directly and specifically with the two internal promoter elements of these genes. We have partially purified Saccharomyces cerevisiae TFIIIC by chromatography on Bio-Rex 70, DEAE-cellulose, and phosphocellulose resins. A 150-kilodalton (kDa) DNA-binding polypeptide copurified with TFIIIC activity. This 150-kDa protein coeluted with the DNA-binding activity of TFIIIC after rechromatography of TFIIIC on phosphocellulose and its elution with a linear salt gradient. The stable and high-affinity interaction of this protein with tRNA genes was demonstrated by the maintenance of a protein-DNA complex under conditions of high ionic strength. Finally, we showed by two criteria that the interaction of this protein with tRNA genes was specific. First, the protein-DNA complex was competed with only by DNA-containing tRNA genes; second, the protein preferentially bound to DNA fragments containing a tRNA gene. These results strongly suggest that the DNA-binding domain of the yeast TFIIIC is contained within this 150-kDa polypeptide.

The Drosophila extramacrochaetae protein antagonizes sequence-specific DNA binding by daughterless/achaete-scute protein complexes

Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 245-255 ◽  
Author(s):  
M. Van Doren ◽  
H.M. Ellis ◽  
J.W. Posakony
Keyword(s):  
Dna Binding ◽  
Cell Fate ◽  
Protein Complexes ◽  
Competitive Inhibitor ◽  
Binding Activity ◽  
Regulatory Function ◽  
Biochemical Basis ◽  
Dna Binding Activity

In Drosophila, a group of regulatory proteins of the helix-loop-helix (HLH) class play an essential role in conferring upon cells in the developing adult epidermis the competence to give rise to sensory organs. Proteins encoded by the daughterless (da) gene and three genes of the achaete-scute complex (AS-C) act positively in the determination of the sensory organ precursor cell fate, while the extramacrochaetae (emc) and hairy (h) gene products act as negative regulators. In the region upstream of the achaete gene of the AS-C, we have identified three ‘E box’ consensus sequences that are bound specifically in vitro by hetero-oligomeric complexes consisting of the da protein and an AS-C protein. We have used this DNA-binding activity to investigate the biochemical basis of the negative regulatory function of emc. Under the conditions of our experiments, the emc protein, but not the h protein, is able to antagonize specifically the in vitro DNA-binding activity of da/AS-C and putative da/da protein complexes. We interpret these results as follows: the heterodimerization capacity of the emc protein (conferred by its HLH domain) allows it to act in vivo as a competitive inhibitor of the formation of functional DNA-binding protein complexes by the da and AS-C proteins, thereby reducing the effective level of their transcriptional regulatory activity within the cell.

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