scholarly journals A Simple Method to Detect the Inhibition of Transcription Factor-DNA Binding Due to Protein–Protein Interactions In Vivo

Genes ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 684 ◽  
Author(s):  
Guangzhe Yang ◽  
Dong Chao ◽  
Zhenhua Ming ◽  
Jixing Xia

Binding of transcription factors (TFs) to cis-regulatory elements (DNA) could modulate the expression of downstream genes, while interactions between TFs and other proteins might inhibit them binding to DNA. Nowadays, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) approaches are usually employed to detect the inhibitory effect. However, EMSA might not reflect the inhibitory effect in vivo. ChIP requires preparation of specific antibody or stable genetic transformation and complicated experimental steps, making it laborious and time-consuming. Here, based on the yeast one-hybrid (Y1H) system, we present a simple method to detect the inhibition of TF–DNA binding due to protein–protein interactions in vivo. When interactions between TFs and other proteins inhibit TFs binding to DNA, the reporter (Aureobasidin A resistance) gene is not activated, thereby inhibiting yeast growth on media containing the AbA antibiotic. Two examples were tested with the newly developed method to demonstrate its feasibility. In conclusion, this method provides an alternative strategy for detecting the inhibition of DNA-binding of TFs due to their interactions with other proteins in vivo.

1993 ◽  
Vol 13 (11) ◽  
pp. 6690-6701
Author(s):  
H Koizumi ◽  
M F Horta ◽  
B S Youn ◽  
K C Fu ◽  
B S Kwon ◽  
...  

The gene encoding the cytolytic protein perforin is selectively expressed by activated killer lymphocytes. To understand the mechanisms underlying the cell-type-specific expression of this gene, we have characterized the regulatory functions and the DNA-protein interactions of the 5'-flanking region of the mouse perforin gene (Pfp). A region extending from residues +62 through -141, which possesses the essential promoter activity, and regions further upstream, which are able to either enhance or suppress gene expression, were identified. The region between residues -411 and -566 was chosen for further characterization, since it contains an enhancer-like activity. We have identified a 32-mer sequence (residues -491 to -522) which appeared to be capable of enhancing gene expression in a killer cell-specific manner. Within this segment, a 9-mer motif (5'-ACAGGAAGT-3', residues -505 to -497; designated NF-P motif), which is highly homologous to the Ets proto-oncoprotein-binding site, was found to interact with two proteins, NF-P1 and NF-P2. NF-P2 appears to be induced by reagents known to up-regulate the perforin message level and is present exclusively in killer cells. Electrophoretic mobility shift assay and UV cross-linking experiments revealed that NF-P1 and NF-P2 may possess common DNA-binding subunits. However, the larger native molecular mass of NF-P1 suggests that NF-P1 contains an additional non-DNA-binding subunit(s). In view of the homology between the NF-P motif and other Ets proto-oncoprotein-binding sites, it is postulated that NF-P1 and NF-P2 belong to the Ets protein family. Results obtained from the binding competition assay, nevertheless, suggest that NF-P1 and NF-P2 are related to but distinct from Ets proteins, e.g., Ets-1, Ets-2, and NF-AT/Elf-1, known to be expressed in T cells.


1998 ◽  
Vol 8 (8) ◽  
pp. 452-458 ◽  
Author(s):  
Sanjay Vashee ◽  
Karsten Melcher ◽  
W.Vivianne Ding ◽  
Stephen Albert Johnston ◽  
Thomas Kodadek

2019 ◽  
Author(s):  
Gareth N. Corry ◽  
Brian D. Sykes ◽  
D. Alan Underhill

ABSTRACTThe PAX (paired box) family is a collection of metazoan transcription factors defined by the paired domain, which confers sequence-specific DNA-binding. Ancestral PAX proteins also contained a homeodomain, which can communicate with the paired domain to modulate DNA-binding. In the present study, we sought to identify determinants of this functional interaction using the paralogous PAX3 and 7 proteins. First, we evaluated a group of heterologous paired domains and homeodomains for the ability to bind DNA cooperatively through formation of a ternary complex (paired domain:homeodomain:DNA). This revealed that capacity for ternary complex formation was unique to the PAX3 and 7 homeodomains and therefore not simply a consequence of DNA-binding. We also found PAX3 and 7 were distinguished by an extended region of conservation N-terminal to the homeodomain (NTE). Phylogenetic analyses established the NTE was restricted to PAX3/7 orthologs of segmented metazoans, indicating it arose in a bilaterian precursor prior to separation of deuterostomes and protostomes. In DNA-binding assays, presence of the NTE caused a decrease in monomeric binding by the PAX3 homeodomain that reflected a lack of secondary structure in 1D-1H-NMR. Nevertheless, this inhibitory effect could be overcome by homeodomain dimerization or cooperative binding with the paired domain, establishing that protein interactions could induce homeodomain folding in the presence of the NTE. Strikingly, the PAX7 counterpart did not impair homeodomain binding, revealing inherent differences that could account for its distinct target profile in vivo. Collectively, these findings identify critical determinants of PAX3 and 7 activity, which contribute to their functional diversification.


1993 ◽  
Vol 13 (11) ◽  
pp. 6690-6701 ◽  
Author(s):  
H Koizumi ◽  
M F Horta ◽  
B S Youn ◽  
K C Fu ◽  
B S Kwon ◽  
...  

The gene encoding the cytolytic protein perforin is selectively expressed by activated killer lymphocytes. To understand the mechanisms underlying the cell-type-specific expression of this gene, we have characterized the regulatory functions and the DNA-protein interactions of the 5'-flanking region of the mouse perforin gene (Pfp). A region extending from residues +62 through -141, which possesses the essential promoter activity, and regions further upstream, which are able to either enhance or suppress gene expression, were identified. The region between residues -411 and -566 was chosen for further characterization, since it contains an enhancer-like activity. We have identified a 32-mer sequence (residues -491 to -522) which appeared to be capable of enhancing gene expression in a killer cell-specific manner. Within this segment, a 9-mer motif (5'-ACAGGAAGT-3', residues -505 to -497; designated NF-P motif), which is highly homologous to the Ets proto-oncoprotein-binding site, was found to interact with two proteins, NF-P1 and NF-P2. NF-P2 appears to be induced by reagents known to up-regulate the perforin message level and is present exclusively in killer cells. Electrophoretic mobility shift assay and UV cross-linking experiments revealed that NF-P1 and NF-P2 may possess common DNA-binding subunits. However, the larger native molecular mass of NF-P1 suggests that NF-P1 contains an additional non-DNA-binding subunit(s). In view of the homology between the NF-P motif and other Ets proto-oncoprotein-binding sites, it is postulated that NF-P1 and NF-P2 belong to the Ets protein family. Results obtained from the binding competition assay, nevertheless, suggest that NF-P1 and NF-P2 are related to but distinct from Ets proteins, e.g., Ets-1, Ets-2, and NF-AT/Elf-1, known to be expressed in T cells.


2005 ◽  
Vol 25 (20) ◽  
pp. 8864-8873 ◽  
Author(s):  
Nibedita Rath ◽  
Zhishan Wang ◽  
Min Min Lu ◽  
Edward E. Morrisey

ABSTRACT The activity of GATA factors is regulated, in part, at the level of protein-protein interactions. LIM domain proteins, first defined by the zinc finger motifs found in the Lin11, Isl-1, and Mec-3 proteins, act as coactivators of GATA function in both hematopoietic and cardiovascular tissues. We have identified a novel GATA-LIM interaction between GATA6 and LMCD1/dyxin. The LIM domains and cysteine-rich domains in LMCD1/dyxin and the carboxy-terminal zinc finger of GATA6 mediate this interaction. Expression of LMCD1/dyxin is remarkably similar to that of GATA6, with high-level expression observed in distal airway epithelium of the lung, vascular smooth muscle, and myocardium. In contrast to other GATA-LIM protein interactions, LMCD1/dyxin represses GATA6 activation of both lung and cardiac tissue-specific promoters. Electrophoretic mobility shift and chromatin immunoprecipitation assays show that LMCD1/dyxin represses GATA6 function by inhibiting GATA6 DNA binding. These data reveal an interaction between GATA6 and LMCD1/dyxin and demonstrate a novel mechanism through which LIM proteins can assert their role as transcriptional cofactors of GATA proteins.


1993 ◽  
Vol 13 (2) ◽  
pp. 1069-1077 ◽  
Author(s):  
J Sidorova ◽  
L Breeden

SWI4 and SWI6 play a crucial role in START-specific transcription in Saccharomyces cerevisiae. SWI4 and SWI6 form a specific complex on the SCB (SWI4/6-dependent cell cycle box) sequences which have been found in the promoters of HO and G1 cyclin genes. Overproduction of SWI4 eliminates the SWI6 dependency of HO transcription in vivo and results in a new SWI6-independent, SCB-specific complex in vitro, which is heterogeneous and reacts with SWI4 antibodies. The C terminus of SWI4 is not required for SWI6-independent binding of SWI4 to SCB sequences, but it is necessary and sufficient for association with SWI6. Both SWI4 and SWI6 contain two copies of a 33-amino-acid TPLH repeat, which has been implicated in protein-protein interactions in other proteins. These repeats are not required for the SWI4-SWI6 association. Alanine substitutions in both TPLH repeats of SWI6 reduce its activity but do not affect the stability of the protein or its association with SWI4. However, these mutations reduce the ability of the SWI4/6 complex to bind DNA. Deletion of the lucine zipper motif in SWI6 also allows SWI4/6 complex formation, but it eliminates the DNA-binding ability of the SWI4/6 complex. This indicates that the integrity of two different regions of SWI6 is required for DNA binding by the SWI4/6 complex. From these data, we propose that the sequence-specific DNA-binding domain resides in SWI4 but that SWI6 controls the accessibility of this domain in the SWI4/6 complex.


1999 ◽  
Vol 19 (4) ◽  
pp. 2577-2584 ◽  
Author(s):  
Elzbieta Biesiada ◽  
Yasuo Hamamori ◽  
Larry Kedes ◽  
Vittorio Sartorelli

ABSTRACT Activation of the human cardiac α-actin (HCA) promoter in skeletal muscle cells requires the integrity of DNA binding sites for the serum response factor (SRF), Sp1, and the myogenic basic helix-loop-helix (bHLH) family. In this study we report that activation of the HCA correlates with formation of a muscle-specific multiprotein complex on the promoter. We provide evidence that proteins eluted from the multiprotein complex specifically react with antibodies directed against myogenin, Sp1, and SRF and that the complex can be assembled in vitro by using the HCA promoter and purified MyoD, E12, SRF, and Sp1. In vitro and in vivo assays revealed a direct association of Sp1 and myogenin-MyoD mediated by the DNA-binding domain of Sp1 and the HLH motif of myogenin. The results obtained in this study indicate that protein-protein interactions and the cooperative DNA binding of transcriptional activators are critical steps in the formation of a transcriptionally productive multiprotein complex on the HCA promoter and suggest that the same mechanisms might be utilized to regulate the transcription of muscle-specific and other genes.


Microbiology ◽  
2014 ◽  
Vol 160 (10) ◽  
pp. 2178-2189 ◽  
Author(s):  
Kuo-Chin Chiu ◽  
Chen-Jyun Lin ◽  
Gwo-Chyuan Shaw

The Bacillus subtilis lutABC operon encodes three iron–sulfur-containing proteins required for l-lactate utilization and involved in biofilm formation. The transcriptional regulator LutR of the GntR family negatively controls lutABC expression. The lutP gene, which is situated immediately upstream of lutR, encodes an l-lactate permease. Here, we show that lutP expression can be strongly induced by l-lactate and is subject to partial catabolite repression by glucose. Disruption of the lutR gene led to a strong derepression of lutP and no further induction by l-lactate, suggesting that the LutR repressor can also negatively control lutP expression. Electrophoretic mobility shift assay revealed a LutR-binding site located downstream of the promoter of lutA or lutP and containing a consensus inverted repeat sequence 5′-TCATC-N1-GATGA-3′. Reporter gene analysis showed that deletion of each LutR-binding site caused a strong derepression of lutA or lutP. These results indicated that these two LutR-binding sites can function as operators in vivo. Moreover, deletion analysis identified a DNA segment upstream of the lutP promoter to be important for lutP expression. In contrast to the truncated LutR of laboratory strains 168 and PY79, the full-length LutR of the undomesticated strain RO-NN-1, and probably many other B. subtilis strains, can directly and negatively regulate lutP transcription. The absence or presence of the N-terminal 21 aa of the full-length LutR, which encompass a small part of the predicted winged helix–turn–helix DNA-binding motif, may probably alter the DNA-binding specificity or affinity of LutR.


1997 ◽  
Vol 17 (5) ◽  
pp. 2920-2932 ◽  
Author(s):  
H Zhang ◽  
G Hu ◽  
H Wang ◽  
P Sciavolino ◽  
N Iler ◽  
...  

Protein-protein interactions are known to be essential for specifying the transcriptional activities of homeoproteins. Here we show that representative members of the Msx and Dlx homeoprotein families form homo- and heterodimeric complexes. We demonstrate that dimerization by Msx and Dlx proteins is mediated through their homeodomains and that the residues required for this interaction correspond to those necessary for DNA binding. Unlike most other known examples of homeoprotein interactions, association of Msx and Dlx proteins does not promote cooperative DNA binding; instead, dimerization and DNA binding are mutually exclusive activities. In particular, we show that Msx and Dlx proteins interact independently and noncooperatively with homeodomain DNA binding sites and that dimerization is specifically blocked by the presence of such DNA sites. We further demonstrate that the transcriptional properties of Msx and Dlx proteins display reciprocal inhibition. Specifically, Msx proteins act as transcriptional repressors and Dlx proteins act as activators, while in combination, Msx and Dlx proteins counteract each other's transcriptional activities. Finally, we show that the expression patterns of representative Msx and Dlx genes (Msx1, Msx2, Dlx2, and Dlx5) overlap in mouse embryogenesis during limb bud and craniofacial development, consistent with the potential for their protein products to interact in vivo. Based on these observations, we propose that functional antagonism through heterodimer formation provides a mechanism for regulating the transcriptional actions of Msx and Dlx homeoproteins in vivo.


1993 ◽  
Vol 13 (2) ◽  
pp. 1069-1077
Author(s):  
J Sidorova ◽  
L Breeden

SWI4 and SWI6 play a crucial role in START-specific transcription in Saccharomyces cerevisiae. SWI4 and SWI6 form a specific complex on the SCB (SWI4/6-dependent cell cycle box) sequences which have been found in the promoters of HO and G1 cyclin genes. Overproduction of SWI4 eliminates the SWI6 dependency of HO transcription in vivo and results in a new SWI6-independent, SCB-specific complex in vitro, which is heterogeneous and reacts with SWI4 antibodies. The C terminus of SWI4 is not required for SWI6-independent binding of SWI4 to SCB sequences, but it is necessary and sufficient for association with SWI6. Both SWI4 and SWI6 contain two copies of a 33-amino-acid TPLH repeat, which has been implicated in protein-protein interactions in other proteins. These repeats are not required for the SWI4-SWI6 association. Alanine substitutions in both TPLH repeats of SWI6 reduce its activity but do not affect the stability of the protein or its association with SWI4. However, these mutations reduce the ability of the SWI4/6 complex to bind DNA. Deletion of the lucine zipper motif in SWI6 also allows SWI4/6 complex formation, but it eliminates the DNA-binding ability of the SWI4/6 complex. This indicates that the integrity of two different regions of SWI6 is required for DNA binding by the SWI4/6 complex. From these data, we propose that the sequence-specific DNA-binding domain resides in SWI4 but that SWI6 controls the accessibility of this domain in the SWI4/6 complex.


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