scholarly journals Multiple sequence-specific transcription factors modulate cytomegalovirus enhancer activity in vitro.

1988 ◽  
Vol 8 (4) ◽  
pp. 1809-1811 ◽  
Author(s):  
P Ghazal ◽  
H Lubon ◽  
L Hennighausen

The possibility of DNA-binding proteins interacting in vitro with the polymerase II transcriptional machinery was explored by using a competition assay with individual target sequences for enhancer-binding factors. Transcription factors binding to at least five specific enhancer sequences mediate the activity of the human cytomegalovirus immediate-early 1 gene in vitro. Furthermore, our data suggest that individual DNA-bound enhancer factors can interact with the promoter transcription complex.

1988 ◽  
Vol 8 (4) ◽  
pp. 1809-1811
Author(s):  
P Ghazal ◽  
H Lubon ◽  
L Hennighausen

The possibility of DNA-binding proteins interacting in vitro with the polymerase II transcriptional machinery was explored by using a competition assay with individual target sequences for enhancer-binding factors. Transcription factors binding to at least five specific enhancer sequences mediate the activity of the human cytomegalovirus immediate-early 1 gene in vitro. Furthermore, our data suggest that individual DNA-bound enhancer factors can interact with the promoter transcription complex.


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.


Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2748 ◽  
Author(s):  
Ae-Ree Lee ◽  
Na-Hyun Kim ◽  
Yeo-Jin Seo ◽  
Seo-Ree Choi ◽  
Joon-Hwa Lee

Z-DNA is stabilized by various Z-DNA binding proteins (ZBPs) that play important roles in RNA editing, innate immune response, and viral infection. In this review, the structural and dynamics of various ZBPs complexed with Z-DNA are summarized to better understand the mechanisms by which ZBPs selectively recognize d(CG)-repeat DNA sequences in genomic DNA and efficiently convert them to left-handed Z-DNA to achieve their biological function. The intermolecular interaction of ZBPs with Z-DNA strands is mediated through a single continuous recognition surface which consists of an α3 helix and a β-hairpin. In the ZBP-Z-DNA complexes, three identical, conserved residues (N173, Y177, and W195 in the Zα domain of human ADAR1) play central roles in the interaction with Z-DNA. ZBPs convert a 6-base DNA pair to a Z-form helix via the B-Z transition mechanism in which the ZBP first binds to B-DNA and then shifts the equilibrium from B-DNA to Z-DNA, a conformation that is then selectively stabilized by the additional binding of a second ZBP molecule. During B-Z transition, ZBPs selectively recognize the alternating d(CG)n sequence and convert it to a Z-form helix in long genomic DNA through multiple sequence discrimination steps. In addition, the intermediate complex formed by ZBPs and B-DNA, which is modulated by varying conditions, determines the degree of B-Z transition.


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.


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.


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