scholarly journals DNA-binding affinity and transcriptional activity of the RelA homodimer of nuclear factor κB are not correlated

2017 ◽  
Vol 292 (46) ◽  
pp. 18821-18830 ◽  
Author(s):  
Maria Carmen Mulero ◽  
De-Bin Huang ◽  
H. Thien Nguyen ◽  
Vivien Ya-Fan Wang ◽  
Yidan Li ◽  
...  
Keyword(s):  
Dna Binding ◽  
Binding Affinity ◽  
Transcriptional Activity ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Dna Binding Affinity

scholarly journals Unexpected implications of STAT3 acetylation revealed by genetic encoding of acetyl-lysine

2019 ◽  
Author(s):  
Yael Belo ◽  
Zack Mielko ◽  
Hila Nudelman ◽  
Ariel Afek ◽  
Oshrit Ben-David ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dna Binding ◽  
Binding Affinity ◽  
Transcriptional Activity ◽  
Extracellular Signals ◽  
Genetic Encoding ◽  
Live Bacteria ◽  
Dna Binding Affinity ◽  
Transcription 3 ◽  
Phosphorylated Stat3

AbstractThe signal transducer and activator of transcription 3 (STAT3) protein is activated by phosphorylation of a specific tyrosine residue (Tyr705) in response to various extracellular signals. STAT3 activity was also found to be regulated by acetylation of Lys685. However, the molecular mechanism by which Lys685 acetylation affects the transcriptional activity of STAT3 remains elusive. By genetically encoding the co-translational incorporation of acetyl-lysine into position Lys685 and co-expression with the Elk receptor tyrosine kinase, we were able to biochemically characterize site-specifically acetylated, and simultaneously acetylated and phosphorylated STAT3. We measured the effect of acetylation on the crystal structure, and DNA binding affinity and specificity of Tyr705-phosphorylated and non-phosphorylated STAT3. In addition, we monitored the deacetylation of acetylated Lys685 by reconstituting the mammalian enzymatic deacetylation reaction in live bacteria. Surprisingly, we found that acetylation, per se, had no effect on the crystal structure, and DNA binding affinity or specificity of STAT3, implying that the previously observed acetylation-dependent transcriptional activity of STAT3 involves an additional cellular component. In addition, we discovered that Tyr705-phosphorylation protects Lys685 from deacetylation in bacteria, providing a new possible explanation for the observed correlation between STAT3 activity and Lys685 acetylation.

A direct requirement of nuclear factor-κB for suppression of apoptosis in ventricular myocytes

2000 ◽  
Vol 279 (3) ◽  
pp. H939-H945 ◽  
Author(s):  
Shareef Mustapha ◽  
Alla Kirshner ◽  
Danielle De Moissac ◽  
Lorrie A. Kirshenbaum
Keyword(s):  
Dna Binding ◽  
Gene Transcription ◽  
Ventricular Myocytes ◽  
Vital Staining ◽  
Fold Increase ◽  
Nuclear Factor Κb ◽  
Nuclear Factor ◽  
Cytoplasmic Factor ◽  
Tnf Α ◽  
Factor Α

Nuclear factor-κB (NF-κB) is a ubiquitously expressed cellular factor regulated by the cytoplasmic factor inhibitor protein κBα (IκBα). Activation of NF-κB by cytokines, including tumor necrosis factor-α (TNF-α), requires the phosphorylation and degradation of IκBα. An anti-apoptotic role for NF-κB has recently been suggested. In the present study, we ascertained whether death-promoting signals and apoptosis mediated by TNF-α are suppressed by NF-κB in postnatal ventricular myocytes. Stimulation of myocytes with TNF-α resulted in a 12.1-fold increase ( P < 0.01) in NF-κB-dependent gene transcription and DNA binding compared with controls. This was accompanied by a corresponding increase in the NF-κB target protein A20 as determined by Western blot analysis. Vital staining revealed that TNF-α was not cytotoxic to myocytes and did not provoke apoptosis. Adenovirus-mediated delivery of a nonphosphorylatable form of IκBα to inactivate NF-κB prevented TNF-α-stimulated NF-κB-dependent gene transcription and nuclear NF-κB DNA binding. Importantly, myocytes stimulated with TNF-α and defective for NF-κB activation resulted in a 2.2-fold increase ( P < 0.001) in apoptosis. To our knowledge, the data provide the first indication that a functional NF-κB signaling pathway is crucial for suppressing death-promoting signals mediated by TNF-α in ventricular myocytes.

scholarly journals Lowering DNA binding affinity of SssI DNA methyltransferase does not enhance the specificity of targeted DNA methylation in E. coli

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Krystyna Ślaska-Kiss ◽  
Nikolett Zsibrita ◽  
Mihály Koncz ◽  
Pál Albert ◽  
Ákos Csábrádi ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Dna Binding ◽  
Binding Affinity ◽  
Dna Methyltransferase ◽  
Restriction Enzymes ◽  
Dna Binding Protein ◽  
E Coli ◽  
Dna Binding Affinity ◽  
Higher Eukaryotes

AbstractTargeted DNA methylation is a technique that aims to methylate cytosines in selected genomic loci. In the most widely used approach a CG-specific DNA methyltransferase (MTase) is fused to a sequence specific DNA binding protein, which binds in the vicinity of the targeted CG site(s). Although the technique has high potential for studying the role of DNA methylation in higher eukaryotes, its usefulness is hampered by insufficient methylation specificity. One of the approaches proposed to suppress methylation at unwanted sites is to use MTase variants with reduced DNA binding affinity. In this work we investigated how methylation specificity of chimeric MTases containing variants of the CG-specific prokaryotic MTase M.SssI fused to zinc finger or dCas9 targeting domains is influenced by mutations affecting catalytic activity and/or DNA binding affinity of the MTase domain. Specificity of targeted DNA methylation was assayed in E. coli harboring a plasmid with the target site. Digestions of the isolated plasmids with methylation sensitive restriction enzymes revealed that specificity of targeted DNA methylation was dependent on the activity but not on the DNA binding affinity of the MTase. These results have implications for the design of strategies of targeted DNA methylation.

UV stimulation induces nuclear factor κB (NF-κB) DNA-binding activity but not transcriptional activation

2001 ◽  
Vol 29 (6) ◽  
pp. 688-691 ◽  
Author(s):  
K. J. Campbell ◽  
N. R. Chapman ◽  
N. D. Perkins
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Cellular Response ◽  
Uv Light ◽  
Binding Protein ◽  
Nuclear Factor Κb ◽  
Camp Response Element Binding ◽  
Binding Activity ◽  
Nuclear Factor ◽  
Dna Binding Activity

The cellular response to DNA-damaging agents is partly mediated by DNA-binding transcription factors such as p53 and nuclear factor κB (NF-κB). Typically NF-κB activation is associated with resistance to apoptosis. Following stimulation with UV light however, NF-κB activation has been shown to be required for programmed cell death. To study this effect further and to determine the relationship between NF-κB and p53 function, we have examined the effect of UV light on U2OS cells. UV stimulation resulted in the activation of NF-κB DNA-binding and the induction of p53. Surprisingly, and in contrast with tumour necrosis factor α stimulation, this UV-induced NF-κB was transcriptionally inert. These observations suggest a model in which the NF-κB switch from an anti-apoptotic to a pro-apoptotic role within the cell results from modulation of its ability to stimulate gene expression, possibly as a result of the ability of p53 to sequester transcriptional co-activator proteins such as p300/CREB (cAMP-response-element-binding protein)-binding protein.

scholarly journals Quantification of transcription factor-DNA binding affinity in a living cell

2015 ◽  
Vol 44 (7) ◽  
pp. 3045-3058 ◽  
Author(s):  
Sergey Belikov ◽  
Otto G. Berg ◽  
Örjan Wrange
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Binding Affinity ◽  
Living Cell ◽  
Dna Binding Affinity
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