We thank S.S. Wang, M. Amar and A. Galla for critical reading of the manuscript. Research reported in this publication was supported by the National Institute of General Medical Sciences of the National Institutes of Health under award numbers RO1GM067837 and RO1GM056006 (to S.A.K). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

1. Construct and Reporter Plasmid Preparation
<ol>
	<li>PCR amplify the promoter regions / &#34;fragments&#34; (preferably ~250 - 500 bp) of the target DNA to be analyzed for further cloning into the entry vector using E. coli (TOP10).</li>
	<li>Upon sequencing confirmation, subclone the positive clone in a compatible pGLacZi expression vector 7 as previously described 8,9,10,<sup cl...

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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Arabidopsis+B-BOX32+interacts+with+CONSTANS-LIKE3+to+regulate+flowering.">Arabidopsis B-BOX32 interacts with CONSTANS-LIKE3 to regulate flowering.</a> Proc Natl Acad Sci USA. 114 (1), 172-177 (2017).</li><li>Helfer, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LUX+ARRHYTHMO+encodes+a+nighttime+repressor+of+circadian+gene+expression+in+the+Arabidopsis+core+clock.">LUX ARRHYTHMO encodes a nighttime repressor of circadian gene expression in the Arabidopsis core clock.</a> Curr Biol : CB. 21 (2), 126-133 (2011).</li><li>Pruneda-Paz, J. 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Authors declare no conflict of interest.

The existing Y1H standard procedure is suitable for identifying a single protein prey binding to its DNA bait. With various technical modifications, the existing system has been harnessed for defining transcriptional regulatory networks. However, TFs are known to function as a part of complexes involving two or more TFs or proteins, with only some of the TF capable of binding to the DNA. Proteins or TFs which possess only the protein-binding domains and lack the ability to bind to DNA are more likely to work in a complex...

In general, to understand protein-DNA interactions, the Y1H assay is the preferred system successfully used in a laboratory setting 1. The basic Y1H assay involves two components: a) a reporter construct with DNA of interest successfully cloned upstream of a gene encoding a reporter protein; and b) an expression construct which will generate a fusion protein between the TF of interest and a yeast transcription activation domain (AD). The DNA of interest is commonly referred to as &#39;bait&#39; while the fusion protein is known as &#39;prey&#39;. In past years, multiple versions of the Y1H assay have been developed to suit specific needs with their own advantages 2. The existing Y1H assay can be successfully implemented to identify and validate interaction of one protein at a time with its DNA bait, but lacks the capability to identify heterodimeric or multimeric protein-DNA interactions.
The method described here is a modified version of the existing Y1H enabling researchers to simultaneously study multiple proteins binding to their target DNA sequence(s). The goal of this assay is to express the protein of interest with an activation domain (pDEST22: TF) and evaluate the activation of the candidate DNA regions fused to a reporter in the presence and/or absence of the interacting protein partner (pDEST32&#916;DBD-TF) in the yeast system. This assay will allow us to determine whether the interaction between these two proteins is required for the activation of the target. This is a GATEWAY cloning compatible system and therefore feasible to use in a regular laboratory setting. Thisprotocol is based on direct transformation, which provides the ease of co-transformation of different TFs in a yeast system. Thus, it is an advantageous strategy to validate the protein complexes binding to their possible DNA targets for in vitro molecular and functional validation for any system. Current techniques such as Tandem affinity purification (TAP) methods are costly and labor intensive but allow detection of protein hetrocomplexes on a large scale 3,4,5. This modified yeast one-hybrid can be successfully performed in a regular lab setting on a small scale (Figure 1) and is also cost effective. The Y1.5H assay can facilitate researchers across the community to test and validate their hypothesis towards defining the role of multimeric protein complex binding to a common DNA target using a heterologous system. Based on the findings, the hypothesis could be validated in vivo in the preferred system of study. Recently, we have used this approach to define the role of a TF and its mode of action to regulate flowering in Arabidopsis 6.

<table border="0" cellpadding="0" cellspacing="0" width="846">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">pDEST22 vector</td>
			<td style="width:132px;">Invitrogen</td>
			<td style="width:157px;">PQ1000101</td>
			<td style="width:332px;">Pro-Quest Two hybrid system kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">pDEST32delatDBD</td>
			<td style="width:132px;">Invitrogen</td>
			<td style="width:157px;">PQ1000102</td>
			<td>Pro-Quest Two hybrid system kit; this vecor is modified. It is pDEST32 minus DNA binding Domain</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">pENTR/D-TOPO Cloning Kit</td>
			<td style="width:132px;">Invitrogen</td>
			<td style="width:157px;">K240020</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">YM4271 Strain</td>
			<td style="width:132px;">Clontech</td>
			<td style="width:157px;">K1603-1</td>
			<td>MATCHMAKER One-Hybrid System</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">pEXP-AD502</td>
			<td style="width:132px;">Invitrogen</td>
			<td style="width:157px;">PQ1000101</td>
			<td>Pro-Quest Two hybrid system kit</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:225px;">GATEWAY LR Clonase II enzyme mix</td>
			<td style="width:132px;">Invitrogen</td>
			<td style="width:157px;">11791020</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">YPDA media</td>
			<td style="width:132px;">Clontech</td>
			<td style="width:157px;">630410</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">SD-Agar</td>
			<td style="width:132px;">Clontech</td>
			<td style="width:157px;">630412</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">SD minimal media</td>
			<td style="width:132px;">Clontech</td>
			<td style="width:157px;">630411</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Uracil DO Supplement</td>
			<td style="width:132px;">Clontech</td>
			<td style="width:157px;">630416</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Tryptophan Do Supplement</td>
			<td style="width:132px;">Clontech</td>
			<td style="width:157px;">630413</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Tris Base</td>
			<td style="width:132px;">Fisher Scientific</td>
			<td style="width:157px;">BP152-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">EDTA</td>
			<td style="width:132px;">Fisher Scientific</td>
			<td style="width:157px;">S311-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">LiAc</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:157px;">L4158</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Saplmon Sperm (10mg/ml)</td>
			<td style="width:132px;">Invitrogen</td>
			<td style="width:157px;">15632011</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">96 well round bottom Plate</td>
			<td>Greiner bio-one</td>
			<td align="right">650101</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">PEG3350</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:157px;">1546547</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">96-deep well block</td>
			<td style="width:132px;">USA Scientific</td>
			<td style="width:157px;">1896-2000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Sealable Foil</td>
			<td style="width:132px;">USA Scientific</td>
			<td style="width:157px;">2923-0110</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Araseal</td>
			<td style="width:132px;">Excel Scientific</td>
			<td style="width:157px;">B-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">2-mercaptoethanol</td>
			<td style="width:132px;">Fisher Scientific</td>
			<td style="width:157px;">034461-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">ONPG</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:157px;">73660</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Na2CO3</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:157px;">223484</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Na2HPO4&#160;</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:157px;">S3264</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">NaH2PO4&#160;</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:157px;">S3139</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">KCL</td>
			<td style="width:132px;">Fisher Scientific</td>
			<td style="width:157px;">BP366-500</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">MgSO4&#160;</td>
			<td style="width:132px;">Sigma-Aldrich</td>
			<td style="width:157px;">83266</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">HCL</td>
			<td style="width:132px;">Fisher Scientific</td>
			<td style="width:157px;">SA54-4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Drybath</td>
			<td style="width:132px;">Thermo Fischer</td>
			<td style="width:157px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Voretx</td>
			<td style="width:132px;">Thermo Fischer</td>
			<td style="width:157px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Centrifgue</td>
			<td style="width:132px;">Eppendorf</td>
			<td style="width:157px;">Centrifuge 5810R</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Plate Reader</td>
			<td style="width:132px;">Molecular Device</td>
			<td style="width:157px;"></td>
			<td>SPECTRAMAX PLUS Microplate Spectrophotometer</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:225px;">Incubator</td>
			<td style="width:132px;">Thermo Fisher</td>
			<td style="width:157px;">Model No. 5250- 37 Degree, 6250-30 degrees</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Shaker Incubator</td>
			<td style="width:132px;">New Brunswick</td>
			<td style="width:157px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Water Bath</td>
			<td style="width:132px;">Thermo Fisher</td>
			<td style="width:157px;">IsoTemp 205</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Puncher</td>
			<td style="width:132px;"></td>
			<td style="width:157px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">50 ml Falocn</td>
			<td style="width:132px;">BD Falcon</td>
			<td style="width:157px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Beaker</td>
			<td style="width:132px;">Nalgene</td>
			<td style="width:157px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Flask</td>
			<td style="width:132px;">Nalgene</td>
			<td style="width:157px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Petriplates (150mm)</td>
			<td style="width:132px;">Greiner bio-one</td>
			<td style="width:157px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

a modified yeast-one hybrid system for heteromeric protein complex-dna interaction studies

Over the years, the yeast one-hybrid assay has proven to be an important technique for the identification and validation of physical interactions between proteins such as transcription factors (TFs) and their DNA target. The method presented here utilizes the underlying concept of the Y1H but is modified further to study and validate protein complexes binding to their target DNA. Hence, it is referred to as the modified yeast one-hybrid (Y1.5H) assay. This assay is cost effective and can be easily performed in a regular laboratory setting. Albeit using a heterologous system, the described method could be a valuable tool to test and validate the heteromeric protein complex binding to their DNA target(s) for functional genomics in any system of study, especially plant genomics.

The general plate set-up procedure for the co-transformation of DNA regions in the yeast cells with protein of interest (Figure 2). The plate set-up can be modified according to the need of the experiment and number of DNA regions/fragments tested. After day-5 of the protocol a well-grown and positive plate should be visible as in Figure 3. In our study, the promoter region of 2600 bp upstream from the start of the transcription ...

Watch this Scientific Journal Video about A Modified Yeast-one Hybrid System for Heteromeric Protein Complex-DNA Interaction Studies at JoVE.com

A Modified Yeast-one Hybrid System for Heteromeric Protein Complex-DNA Interaction Studies

The modified yeast one-hybrid assay described here is an extension of the classical yeast one-hybrid (Y1H) assay to study and validate the heteromeric protein complex-DNA interaction in a heterologous system for any functional genomics study.

Over the years, the yeast one-hybrid assay has proven to be an important technique for the identification and validation of physical interactions between ...

The overall goal of this experiment is to study and validate the heteromeric protein complex-DNA interaction in a heterologous system for any functional genomic study in a regular laboratory setting. This method can help answer key questions in functional genomics field, such as planned genomics. The main advantage of this technique is that it detects protein DNA interactions involving more than one protein or transcription factor.Begin this procedure on the afternoon of what will be designated as day one. Start a 5 milliliter culture in synthetic defined or SD medium without uracil from a freshly streaked Petri dish. Incubate overnight in a 30 degree Celsius shaker.On the following afternoon, inoculate 10 milliliters of YPDA medium with 500 microliters of the overnight culture and incubate overnight in a 30 degree Celsius shaker. Early in the morning of the following day, inoculate 100 milliliters of YPDA medium with 2 milliliters of the overnight culture. Grow this fresh culture at 30 degrees Celsius until the optical density at 600 nanometers, reaches 0.4 to 0.8.Centrifuge at 1000 times G and 21 degrees Celsius for 5 minutes. Discard the supernatant. Add 10 milliliters of sterile water and reconstitute the pellet by vortexing.Centrifuge at 1000 times G and 21 degrees Celsius for five minutes. Discard the supernatant, add 2 milliliters of TE lithium acetate, and reconstitute the pellet by vortexing. Centrifuge at 1000 times G and 21 degrees Celsius for five minutes.Discard the supernatant. Add 4 milliliters of TE lithium acetate plus 400 microliters of salmon sperm DNA and resuspend the pellet by pipetting up and down. The cells are now ready for transformation as demonstrated in the next segment.Co-transformation of the cells is performed in a 96 well U-bottom mixing plate. First, distribute 20 microliters of competent cells per well in the 96 well plate. Then, add to the wells, 150 nanograms each of the two plasmids and the normalization control.This schematic shows the general plate set up for the co-transformation of the yeast cells with protein of interest. The plate set up can be modified according to the need of the experiment and number of DNA regions or fragments tested. Add 100 microliters of TE lithium acetate polyethylene glycol per well and mix three times by pipetting.Cover the plate with a breathable seal and incubate at 30 degrees Celsius for 20 to 30 minutes. Heat shock at 42 degrees Celsius for precisely 20 minutes. After the heat shock, centrifuge at 1000 times G and 21 degrees Celsius for 5 minutes.Use a multichannel pipette to remove the supernatant. Add 110 microliters of TE and mix. Centrifuge again for 5 minutes.Remove 100 microliters of the supernatant from each well. Immerse a puncher in 100%ethanol, flame it, wait for one minute for the puncher pins to cool, and then use the sterile puncher to resuspend the pellet. Transfer cells onto SD tryptophan and lucine drop out auger plates.Incubate the plates at 30 degrees Celsius for two days. On the afternoon of day five, retrieve the auger plates from the incubator. Fill each well of the sterile 96 well u-bottom mixing plate with 50 microliters of TE.Prewet a sterile puncher in TE, punch the colonies from the SD tryptophan and lucine drop out plate, and resuspend them in the TE filled plate.Transfer the colonies onto new SD tryptophan and lucine drop out auger plates, for optimal surface coverage. Incubate the plates at 30 degrees Celsius for 2 days. On the afternoon of day 7, retrieve the auger plates from the incubator.Fill each well of a sterile 96 well u-bottom mixing plate with 50 microliters of SD tryptophan and lucine drop out medium. Fill each well of a sterile 96 deep well block with 180 microliters of SD tryptophan and lucine drop out medium. Sterilize the puncher, prewet the puncher and medium, and transfer colonies from the plate to the wells that each contain 50 microliters of medium.Transfer 20 microliters of yeast to the 180 microliters of SD tryptophan and lucine drop out medium. Seal the block with a breathable seal, and incubate at 30 degrees Celsius with shaking for 36 hours. On the morning of day nine, transfer 100 microliters of culture to 500 microliters of YPDA medium in a sterilized 96 deep well block.Cover with a breathable seal and incubate at 30 degrees Celsius with agitation at 200 rpm for three to five hours. After three to five hours, resuspend the culture and transfer 125 microliters from each well to a spectrophotometer plate. Measure the optical density at 600 nanometers to ensure it is between 0.3 and 0.6.Centrifuge the remaining cells in the deep well block at 3000 times G and 21 degrees Celsius for 10 minutes. Remove the supernatant by inverting. Add 200 microliters of Z buffer to each well and vortex.Centrifuge at 3000 G and 21 degrees Celsius for five minutes. Remove the supernatant by inverting. Add 21 microliters of Z buffer to each well and vortex.Cover the plate with sealing foil that is resistant to freeze thaw cycles. In a fume hood, perform 4 cycles of freeze/thaw using liquid nitrogen and a 42 degree Celsius water bath. Add 200 microliters of freshly prepared Z buffer beta mercaptoethanol ONPG solution to each well.Incubate at 30 degrees Celsius for 17 to 24 hours or until color develops. On the morning of day 10, check that the color has developed. Add 110 microliters of one molar sodium carbonate to each well to stop the reaction.Record the time and vortex the plate. Centrifuge at 3000 times G and 21 degrees Celsius for ten minutes. Use a multichannel pipette to transfer 125 microliters of supernatant from each well to a spectrophotometer plate.Measure the optical density at 420 nanometers. Calculate beta galactosidase activity in a spread sheet as described in the text protocol. In this study, the promoter region of 2600 base pairs upstream from the start of the transcription start site was segmented into six regions or fragments.This photo is an example of a well-grown and positive plate after day five of the protocol. In this representative result, DNA fragments one and four show positive interaction with the protein A and B complex. Upon the measurement of beta golactisidase activity, fragment one shows four fold induction of the reporter gene activity.It is important to remember that this procedure is recommended for obtaining information on DNA regions only after the confirmation of the proposed protein protein interaction and is not designed to provide information of target sites. Following this procedures, other methods, such as chip assay and Msar can be preformed in order to answer additional questions. For example, identifying the target sites in vivo.After watching this video, you should have a good understanding of how to test and validate the role of multimeric protein complexes binding to a common DNA target.

a-modified-yeast-one-hybrid-system-for-heteromeric-protein-complex

Research

JoVE Journal

Biochemistry

11.2K Views.  University of Southern California. The overall goal of this experiment is to study and validate the heteromeric protein complex-DNA interaction in a heterologous system for any functional genomic study in a regular laboratory setting. This method can help answer key questions in functional genomics field, such as planned genomics. The main advantage of this technique is that it detects protein DNA interactions involving more than one protein or transcription factor.Begin this procedure on the afternoon of what will be d...