scholarly journals Regulation of Transcription by Hypoxia Requires a Multiprotein Complex That Includes Hypoxia-Inducible Factor 1, an Adjacent Transcription Factor, and p300/CREB Binding Protein

1998 ◽  
Vol 18 (7) ◽  
pp. 4089-4096 ◽  
Author(s):  
Benjamin L. Ebert ◽  
H. Franklin Bunn

ABSTRACT Molecular adaptation to hypoxia depends on the binding of hypoxia-inducible factor 1 (HIF-1) to cognate response elements in oxygen-regulated genes. In addition, adjacent sequences are required for hypoxia-inducible transcription. To investigate the mechanism of interaction between these cis-acting sequences, the multiprotein complex binding to the lactate dehydrogenase A (LDH-A) promoter was characterized. The involvement of HIF-1, CREB-1/ATF-1, and p300/CREB binding protein (CBP) was demonstrated by techniques documenting in vitro binding, in combination with transient transfections that test the in vivo functional importance of each protein. In both the LDH-A promoter and the erythropoietin 3′ enhancer, formation of multiprotein complexes was analyzed by using biotinylated probes encompassing functionally critical cis-acting sequences. Strong binding of p300/CBP required interactions with multiple DNA binding proteins. Thus, the necessity of transcription factor binding sites adjacent to a HIF-1 site for hypoxically inducible transcription may be due to the requirement of p300 to interact with multiple transcription factors for high-affinity binding and activation of transcription. Since it has been found to interact with a wide range of transcription factors, p300 is likely to play a similar role in other genes, mediating interactions between DNA binding proteins, thereby activating stimulus-specific and tissue-specific gene transcription.

2020 ◽  
Author(s):  
Kusal T. G. Samarasinghe ◽  
Saul Jaime-Figueroa ◽  
Katherine Dai ◽  
Zhenyi Hu ◽  
Craig M. Crews

AbstractMany diseases, including cancer, stem from aberrant activation and overexpression of oncoproteins that are associated with multiple signaling pathways. Although proteins with catalytic activity are able to be successfully drugged, the majority of other protein families, such as transcription factors, remain intractable due to their lack of ligandable sites. In this study, we report the development of TRAnscription Factor TArgeting Chimeras (TRAFTACs) as a generalizable strategy for targeted transcription-factor degradation. Herein, we show that TRAFTACs, which consist of a chimeric oligonucleotide that simultaneously binds to the transcription-factor of interest (TOI) and to HaloTag fused dCas9 protein, can induce degradation of the former via the proteasomal pathway. Application of TRAFTACs to two oncogenic TOIs, NF-κB and brachyury, suggests that TRAFTACs can be successfully employed for the targeted degradation of other DNA-binding proteins with minor changes to the chimeric oligonucleotide.


2012 ◽  
Vol 103 (6) ◽  
pp. 1028-1037 ◽  
Author(s):  
Yanjue Wu ◽  
Jean-Philippe Richard ◽  
Shervin D. Wang ◽  
Prakash Rath ◽  
John Laterra ◽  
...  

2015 ◽  
Vol 6 (1) ◽  
pp. 745-751 ◽  
Author(s):  
Ying Liu ◽  
Wenlu Zheng ◽  
Wan Zhang ◽  
Nan Chen ◽  
Yang Liu ◽  
...  

A dual-probe system can specifically capture DNA-binding proteins with an unmodified binding site.


1997 ◽  
Vol 324 (3) ◽  
pp. 729-736 ◽  
Author(s):  
Valeria FACCHINETTI ◽  
Livio LOFFARELLI ◽  
Sabine SCHREEK ◽  
Michael OELGESCHLÄGER ◽  
Bernhard LÜSCHER ◽  
...  

The A-Myb transcription factor belongs to the Myb family of oncoproteins and is likely to be involved in the regulation of proliferation and/or differentiation of normal B cells and Burkitt's lymphoma cells. To characterize in detail the domains of A-Myb that regulate its function, we have generated a series of deletion mutants and have investigated their trans-activation potential as well as their DNA-binding activity. Our results have allowed us to delineate the trans-activation domain as well as two separate regulatory regions. The boundaries of the trans-activation domain (amino acid residues 218–319) are centred on a sequence rich in charged amino acids (residues 259–281). A region (residues 320–482) localized immediately downstream of the trans-activation domain and containing a newly identified conserved stretch of 48 residues markedly inhibits specific DNA binding. Finally the last 110 residues of A-Myb (residues 643–752), which include a sequence conserved in all mammalian myb genes (region III), negatively regulate the maximal trans-activation potential of A-Myb. We have also investigated the functional interaction between A-Myb and the nuclear adaptor molecule CBP [cAMP response element-binding protein (CREB)-binding protein]. We demonstrate that CBP synergizes with A-Myb in a dose-dependent fashion, and that this co-operative effect can be inhibited by E1A and can also be observed with the CBP homologue p300. We show that this functional synergism requires the presence of the A-Myb charged sequence and that it involves physical interaction between A-Myb and the CREB-binding domain of CBP.


2016 ◽  
Author(s):  
Long Qian ◽  
Edo Kussell

AbstractEctopic DNA binding by transcription factors and other DNA binding proteins can be detrimental to cellular functions and ultimately to organismal fitness. The frequency of protein-DNA binding at non-functional sites depends on the global composition of a genome with respect to all possible short motifs, or k-mer words. To determine whether weak yet ubiquitous protein-DNA interactions could exert significant evolutionary pressures on genomes, we correlate in vitro measurements of binding strengths on all 8-mer words from a large collection of transcription factors, in several different species, against their relative genomic frequencies. Our analysis reveals a clear signal of purifying selection to reduce the large number of weak binding sites genome-wide. This evolutionary process, which we call global selection, has a detectable hallmark in that similar words experience similar evolutionary pressure, a consequence of the biophysics of protein-DNA binding. By analyzing a large collection of genomes, we show that global selection exists in all domains of life, and operates through tiny selective steps, maintaining genomic binding landscapes over long evolutionary timescales.


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