We thank the staff within the Institute of Human Genetics for NGS library preparation and sequencing. We thank Einat Snir for her expertise in preparing genomic library fragments for the Y2H plasmid library made here. This work was supported by National Institutes of Health: NIH R21 EB021870-01A1 and by NSF Research Project Grant: 1517110.

<ol>
	<li>Fields, S., Song, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+genetic+system+to+detect+protein-protein+interactions.">A novel genetic system to detect protein-protein interactions.</a> Nature. 340 (6230), 245-246 (1989).</li><li>Bruckner, A., Polge, C., Lentze, N., Auerbach, D., Schlattner, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Yeast+two-hybrid,+a+powerful+tool+for+systems+biology.">Yeast two-hybrid, a powerful tool for systems biology.</a> International Journal of Molecular Sciences. 10 (6), 2763-2788 (2009).</li><li>Vidal, M., Fields, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+yeast+two-hybrid+assay:+still+finding+connections+after+25+years.">The yeast two-hybrid assay: still finding connections after 25 years.</a> Nature Methods. 11 (12), 1203-1206 (2014).</li><li>Pashkova, N., 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=DEEPN+as+an+Approach+for+Batch+Processing+of+Yeast+2-Hybrid+Interactions.">DEEPN as an Approach for Batch Processing of Yeast 2-Hybrid Interactions.</a> Cell Reports. 17 (1), 303-315 (2016).</li><li>Rajagopala, S. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mapping+the+Protein-Protein+Interactome+Networks+Using+Yeast+Two-Hybrid+Screens.">Mapping the Protein-Protein Interactome Networks Using Yeast Two-Hybrid Screens.</a> Advances in Experimental Medicine and Biology. 883, 187-214 (2015).</li><li>Weimann, M., 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=A+Y2H-seq+approach+defines+the+human+protein+methyltransferase+interactome.">A Y2H-seq approach defines the human protein methyltransferase interactome.</a> Nature Methods. 10 (4), 339-342 (2013).</li><li>Yachie, N., 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=Pooled-matrix+protein+interaction+screens+using+Barcode+Fusion+Genetics.">Pooled-matrix protein interaction screens using Barcode Fusion Genetics.</a> Molecular Systems Biology. 12 (4), 863 (2016).</li><li>Trigg, S. 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=CrY2H-seq:+a+massively+multiplexed+assay+for+deep-coverage+interactome+mapping.">CrY2H-seq: a massively multiplexed assay for deep-coverage interactome mapping.</a> Nature Methods. , (2017).</li><li>Estojak, J., Brent, R., Golemis, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+of+two-hybrid+affinity+data+with+in+vitro+measurements.">Correlation of two-hybrid affinity data with in vitro measurements.</a> Molecular and Cellular Biology. 15 (10), 5820-5829 (1995).</li><li>Rajagopala, S. V., Hughes, K. T., Uetz, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Benchmarking+yeast+two-hybrid+systems+using+the+interactions+of+bacterial+motility+proteins.">Benchmarking yeast two-hybrid systems using the interactions of bacterial motility proteins.</a> Proteomics. 9 (23), 5296-5302 (2009).</li><li>James, P., Halladay, J., Craig, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genomic+libraries+and+a+host+strain+designed+for+highly+efficient+two-hybrid+selection+in+yeast.">Genomic libraries and a host strain designed for highly efficient two-hybrid selection in yeast.</a> Genetics. 144 (4), 1425-1436 (1996).</li><li>Barbas, C. F., Burton, D. R., Scott, J. K., Silverman, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitation+of+DNA+and+RNA.">Quantitation of DNA and RNA.</a> CSH Protoc. 2007, pdb ip47 (2007).</li><li>Sambrook, J., Russell, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SDS-Polyacrylamide+Gel+Electrophoresis+of+Proteins.">SDS-Polyacrylamide Gel Electrophoresis of Proteins.</a> Cold Spring Harbor Protocols. 2006 (4), (2006).</li><li>Towbin, H., Staehelin, T., Gordon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophoretic+transfer+of+proteins+from+polyacrylamide+gels+to+nitrocellulose+sheets:+procedure+and+some+applications.">Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some applications.</a> Proceedings of the National Academy of Sciences USA. 76 (9), 4350-4354 (1979).</li><li>Alegria-Schaffer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Western+blotting+using+chemiluminescent+substrates.">Western blotting using chemiluminescent substrates.</a> Methods in Enzymology. 541, 251-259 (2014).</li><li>Lee, P. Y., Costumbrado, J., Hsu, C. Y., Kim, Y. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Agarose+gel+electrophoresis+for+the+separation+of+DNA+fragments.">Agarose gel electrophoresis for the separation of DNA fragments.</a> Journal of Visualized Experiments. (62), (2012).</li><li>Harper, J. W., Adami, G. R., Wei, N., Keyomarsi, K., Elledge, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+p21+Cdk-interacting+protein+Cip1+is+a+potent+inhibitor+of+G1+cyclin-dependent+kinases.">The p21 Cdk-interacting protein Cip1 is a potent inhibitor of G1 cyclin-dependent kinases.</a> Cell. 75 (4), 805-816 (1993).</li></ol>

The authors have nothing to disclose

Here we provide a guide for how to perform Y2H assays in batch using optimized methods. There are a few critical steps in the procedure to help ensure that the population of yeast that would be placed under selection is representative of the starting library and that enough of the starting yeast population is used to undergo selection to limit variability. Importantly, these benchmarks are relatively easy to achieve alongside adapting the methods and materials for a traditional Y2H assay, thus making this approach access...

A complete understanding of cell biological processes relies on finding the protein interaction networks that underlie their molecular mechanisms. One approach to identify protein interactions is the yeast 2-hybrid (Y2H) assay, which works by assembling a functioning chimeric transcription factor once two protein domains of interest bind to one another1. A typical Y2H screen is performed by creating a population of yeast that houses both a library of plasmids encoding interacting proteins fused to a transcriptional activator (e.g., &#39;prey&#39; fusion protein) and a given &#39;bait&#39; plasmid comprised of the protein of interest fused to a DNA binding domain (e.g., the Gal4 DNA-binding domain that binds to the Gal4-upstream activating sequence). One of the main advantages of the Y2H approach is that it is relatively easy and inexpensive to conduct in a typical laboratory equipped for routine molecular biological work2. However, when traditionally performed, a user samples individual colonies that arise upon selection for a positive Y2H interaction. This severely limits the number of library &#39;prey&#39; clones that can be surveyed. This problem is compounded when the abundance of a particular interacting prey is very high relative to the others, diminishing the chance of detecting interaction from low abundance prey plasmids.
One solution for using the Y2H principle in comprehensive coverage of the proteome is the use of a matrix-formatted approach wherein an array containing known individual prey plasmids can be digitally interrogated. However, such an approach requires an infrastructure that is not readily accessible or cost-effective to individual investigators who are interested in defining the interactome of a small number of proteins or domains3. In addition, very complex prey libraries that may encode multiple fragments of interacting proteins would expand the size of such matrix arrays to impractical sizes. An alternative is to perform assays with complex libraries in batches and assess the presence of interacting clones using massive parallel high-throughput sequencing4. This can be applied to assay the presence of prey plasmids that arise in multiple colonies using a typical Y2H formatted approach in which yeast cells housing an interacting pair of fusion proteins are allowed to grow on a plate5,6. This general idea can be accentuated to increase query of both multiple bait and prey components at the same time7,8.
Still, many investigations require an easier yet more focused effort on just a few protein &#39;baits&#39; and can benefit more by an exhaustive and semi-quantitative query of a single complex prey library. We have developed and validated an approach to perform wide-scale protein interaction studies using a Y2H principle in batch format4. This uses the rate of expansion of a particular prey plasmid as a proxy for the relative strength of Y2H interaction9. Deep sequencing of all plasmids within a population subjected to normal growth or selective growth conditions produces a complete map of clones that yield strong and weak Y2H interactions. The repertoire of interactors can be obtained and directly compared across multiple bait plasmids. The resulting workflow termed DEEPN (Dynamic Enrichment for Evaluation of Protein Networks) can thus be used to identify differential interactomes from the same prey libraries to identify proteins, allowing comparison between one protein vs. another.
Here, we demonstrate DEEPN and introduce improvements in the laboratory methods that facilitate its use, which are outlined in Figure 1. Significant improvements include:
Generation of prey yeast populations. One of the key requirements of DEEPN is generating populations of yeast with different bait plasmids that have the same distribution of the plasmid prey libraries. Equivalent baseline populations of the prey plasmid library are essential for making accurate comparisons between the interactomes of different baits. This is best achieved when a library plasmid is already housed in a haploid yeast population and moving a given bait plasmid into that population is achieved by mating to produce a diploid. Here, we provide a clear guide in how to make such populations using commercial libraries housed in haploid yeast. Although we found methods that generate a high number of diploids, the overall mating efficiency of these commercial library-containing yeast strains was low. Therefore, we constructed a new strain that can house prey libraries that yields far more diploids per mating reaction.
New set of bait plasmids. Many current plasmids that express &#39;bait&#39; fusion proteins comprised of the protein of interest and a DNA-binding domain are 2&#181;-based, allowing them to amplify their copy number. This copy number can be quite variable in the population and lead to variability in the Y2H transcriptional response. This in turn could skew the ability to gauge the strength of a given protein interaction based on the growth response of cells under selection. This can be partly address by using a low copy plasmid, some of which have been previously described such as the commercially available pDEST3210. We constructed a new bait plasmid (pTEF-GBD) that produces Gal4-DNA-binding domain fusion proteins within a TRP1 centromere-based low copy plasmid carrying the Kanr resistance gene that also allows cloning of bait fragments both upstream and downstream of the Gal4 DNA-binding domain.
New High-Density Y2H fragment library. We constructed a new plasmid to house Y2H prey libraries and used it to build a highly complex Y2H library made of randomly sheared fragments of genomic DNA from Saccharomyces cerevisiae. Sequence analysis showed that this library had over 1 million different elements, far more complex than previously described yeast genomic Y2H plasmid libraries11. With this new library, we were able to show that the DEEPN workflow is robust enough to accommodate complex libraries with many different plasmids in a manner that is reliable and reproducible.

<table><tbody><tr><td>Illumina HiSeq 4000</td><td>Illumina</td><td></td><td>deep sequencing platform</td></tr><tr><td>Monoclonal anti-HA antibodies</td><td>Biolegend</td><td>901514</td><td>Primary Antibody to detect expression of HA in pGal4AD constructs</td></tr><tr><td>Polyclonal anti-myc antibodies</td><td>QED Biosciences Inc</td><td>18826</td><td>Primary Antibody to detect expression of MYC in pTEF-GBD constructs</td></tr><tr><td>NarI</td><td>New England BioLabs</td><td>R0191S</td><td></td></tr><tr><td>EcoRI-HF</td><td>New England BioLabs</td><td>R3101S</td><td></td></tr><tr><td>BamHI-HF</td><td>New England BioLabs</td><td>R3236S</td><td></td></tr><tr><td>XhoI</td><td>New England BioLabs</td><td>R0146S</td><td></td></tr><tr><td>Polyethylene Glycol 3350, powder</td><td>J.T. Baker</td><td>U2211-08</td><td></td></tr><tr><td>Salmon Sperm DNA</td><td>Trevigen, Inc sold by Fisher Scientific</td><td>50-948-286</td><td>carrier DNA for yeast transformation section 3.2.1.</td></tr><tr><td>Kanamycin Monosulfate</td><td>Research Products International</td><td>K22000</td><td></td></tr><tr><td>LE Agarose</td><td>GeneMate</td><td>E-3120-500</td><td>used for making DNA agarose gels</td></tr><tr><td>Sodium Chloride</td><td>Research Products International</td><td>S23025</td><td></td></tr><tr><td>Tryptone</td><td>Research Products International</td><td>T60060</td><td></td></tr><tr><td>D-Sorbitol</td><td>Research Products International</td><td>S23080</td><td></td></tr><tr><td>Lithium Acetate Dihydrate</td><td>MP Biomedicals</td><td>155256</td><td></td></tr><tr><td>Calcium Chloride</td><td>ThermoFisher</td><td>C79</td><td></td></tr><tr><td>EDTA Sodium Salt</td><td>Research Products International</td><td>E57020</td><td></td></tr><tr><td>Yeast Extract Powder</td><td>Research Products International</td><td>Y20020</td><td></td></tr><tr><td>Yeast Nitrogen Base (ammonium sulfate) w/o amino acids</td><td>Research Products International</td><td>Y20040</td><td></td></tr><tr><td>CSM-Trp-Leu+40ADE</td><td>Formedium</td><td>DCS0789</td><td></td></tr><tr><td>CSM-Trp-Leu-His+40ADE</td><td>Formedium</td><td>DCS1169</td><td></td></tr><tr><td>CSM-Leu-Met</td><td>Formedium</td><td>DCS0549</td><td></td></tr><tr><td>CSM-Trp-Met</td><td>Bio 101, Inc</td><td>4520-922</td><td></td></tr><tr><td>L-Methionine</td><td>Formedium</td><td>DOC0168</td><td></td></tr><tr><td>Adenine</td><td>Research Products International</td><td>A11500</td><td></td></tr><tr><td>D-(+)-Glucose</td><td>Research Products International</td><td>G32045</td><td></td></tr><tr><td>Bacto Agar</td><td>BD</td><td>214010</td><td>used for making media plates in section 1</td></tr><tr><td>Peptone</td><td>Research Products International</td><td>P20240</td><td></td></tr><tr><td>3-amino-1,2,4 Triazole</td><td>Sigma</td><td>A8056</td><td></td></tr><tr><td>2-Mercaptoehanol (BME)</td><td>Sigma-Aldrich</td><td>M6250</td><td></td></tr><tr><td>Zymolyase 100T</td><td>USBiological</td><td>Z1004</td><td></td></tr><tr><td>Potassium phosphate dibasic</td><td>Sigma</td><td>P8281</td><td></td></tr><tr><td>Phenol:Chloroform:IAA</td><td>Ambion</td><td>AM9732</td><td></td></tr><tr><td>Ammonium Acetate</td><td>Sigma-Aldrich</td><td>238074</td><td></td></tr><tr><td>Ethanol</td><td>Decon Laboratories, INC</td><td>2716</td><td></td></tr><tr><td>RNAse A</td><td>ThermoFisher</td><td>EN0531</td><td></td></tr><tr><td>Urea</td><td>Research Products International</td><td>U20200</td><td></td></tr><tr><td>SDS</td><td>Research Products International</td><td>L22010</td><td></td></tr><tr><td>glycerol</td><td>Sigma Aldrich</td><td>G5516</td><td></td></tr><tr><td>Tris-HCl</td><td>Gibco</td><td>15506-017</td><td></td></tr><tr><td>bromophenol blue</td><td>Amresco</td><td>449</td><td></td></tr><tr><td>Gibson Assembly Cloning Kit</td><td>New England Biolabs</td><td>E5510S</td><td>Rapid assembly method for cloning of plasmids in section 2</td></tr><tr><td>NEBNext High-Fidelity 2x PCR Master Mix</td><td>New England Biolabs</td><td>M0541S</td><td>Used for amplification of products for Gibson Assembly in Section 2.3 as well assample preparation for DEEPN deep sequencing in section 6.2.1</td></tr><tr><td>Ethidium Bromide</td><td>Amresco</td><td>0492-5G</td><td></td></tr><tr><td>QIAquick PCR purification kit</td><td>Qiagen</td><td>28104</td><td>Used for purification of pcr products in section 6.2.3</td></tr><tr><td>Qiaquick DNA Gel Extraction Kit</td><td>Qiagen</td><td>28704</td><td>Used for purification of digested pTEF-GBD in section 2.1</td></tr><tr><td>KAPA Hyper Prep kit</td><td>KAPA Biosystems</td><td>KK8500</td><td>preparation kit for deep sequencing</td></tr><tr><td>Codon optimization</td><td>http://www.jcat.de</td><td></td><td></td></tr><tr><td>Codon optimization</td><td>https://www.idtdna.com/CodonOpt</td><td></td><td></td></tr><tr><td>gBlocks</td><td>Integrated DNA Technologies</td><td></td><td>DNA fragments used for cloning in Section 2.2</td></tr><tr><td>Strings</td><td>Thermofisher</td><td></td><td>DNA fragments used for cloning in Section 2.2</td></tr><tr><td>GenCatch Plasmid DNA mini-prep Kit</td><td>EPOCH Life Sciences</td><td></td><td>Used to prepare quantities of DNA in Section 2.3</td></tr><tr><td>Covaris E220</td><td>Covaris</td><td></td><td>high performance ultra-sonicator in section 7</td></tr><tr><td>oligo nucelotide 5&amp;rsquo;- CGGTCTT&lt;br/&gt; CAATTTCTCAAGTTTCAG -3&amp;rsquo;</td><td>Integrated DNA Technologies or Thermofisher</td><td></td><td>used for pcr amplification and sequencing 5&#039; insert pTEF-GBD during plasmid construction</td></tr><tr><td>oligo nucelotide 5&amp;rsquo;-GAGTAACG&lt;br/&gt; ACATTCCCAGTTGTTC-3&amp;rsquo;</td><td>Integrated DNA Technologies or Thermofisher</td><td></td><td>used for pcr amplification and sequencing 5&#039; insert pTEF-GBD during plasmid construction</td></tr><tr><td>oligo nucelotide 5&amp;rsquo;-CACCGTAT&lt;br/&gt; TTCTGCCACCTCTTCC-3&amp;rsquo;</td><td>Integrated DNA Technologies or Thermofisher</td><td></td><td>used for pcr amplification and sequencing 3&#039; insert pTEF-GBD during plasmid construction</td></tr><tr><td>oligo nucelotide 5&amp;rsquo;-GCAACCGC&lt;br/&gt; ACTATTTGGAGCGCTG-3&amp;rsquo;</td><td>Integrated DNA Technologies or Thermofisher</td><td></td><td>used for pcr amplification and sequencing 3&#039; insert pTEF-GBD during plasmid construction</td></tr><tr><td>oligonucleotide 5&amp;rsquo;-GTTCCGATG&lt;br/&gt; CCTCTGCGAGTG-3&amp;rsquo;</td><td>Integrated DNA Technologies or Thermofisher</td><td></td><td>5&#039; Pimer used for insert amplification of pGAL4AD</td></tr><tr><td>oligonucelotide 5&amp;rsquo;-GCACATGCT&lt;br/&gt; AGCGTCAAATACC-3&amp;rsquo;</td><td>Integrated DNA Technologies or Thermofisher</td><td></td><td>3&#039; Pimer used for insert amplification of pGAL4AD</td></tr><tr><td>oligonucelotide 5&amp;rsquo;-ACCCAAGCA&lt;br/&gt; GTGGTATCAACG-3&amp;rsquo;</td><td>Integrated DNA Technologies or Thermofisher</td><td></td><td>5&#039; Pimer used for insert amplification of pGADT7</td></tr><tr><td>oligonucelotide 5&amp;rsquo;- TATTTAGA&lt;br/&gt; AGTGTCAACAACGTA -3&amp;rsquo;</td><td>Integrated DNA Technologies or Thermofisher</td><td></td><td>3&#039; Pimer used for insert amplification of pGADT7</td></tr><tr><td>PJ69-4A MatA yeast strain</td><td>http://depts.washington.edu/yeastrc/ James P, Halladay J, Craig EA: Genomic Libraries and a host strain designed for highly efficient two-hybrid selection in yeast. GENETICS 1996 144:1425-1436</td><td></td><td>MATA leu2-3,112 ura3-52 trp1-901 his3-200 gal4D, gal80D, GAL-ADE2 lys2::GAL1-HIS3 met2::GAL7</td></tr><tr><td>pTEF-GBD</td><td>Dr. Robert Piper Lab</td><td></td><td>Gal4-DNA binding doimain expression plasmid</td></tr><tr><td>pGal4AD (pPL6343)</td><td>Dr. Robert Piper Lab</td><td></td><td>Gal4-activation domain expression plasmid</td></tr><tr><td>100 mm petri dishes</td><td>Kord-Vallmark sold by VWR</td><td>2900</td><td></td></tr><tr><td>125 mL PYREX Erlenmeyer flask</td><td>Fisher Scientific</td><td>S63270</td><td></td></tr><tr><td>250 mL PYREX Erlenmeyer flask</td><td>Fisher Scientific</td><td>S63271</td><td></td></tr><tr><td>1,000 mL PYREX Erlenmeyer flask</td><td>Fisher Scientific</td><td>S63274</td><td></td></tr><tr><td>2,000 mL PYREX Erlenmeyer flask</td><td>Fisher Scientific</td><td>S63275</td><td></td></tr><tr><td>20 X 150 mm Disposable Culture Tube</td><td>Thermofisher</td><td>14-961-33</td><td></td></tr><tr><td>pipet-aid</td><td>Drummond</td><td>4-000-100</td><td></td></tr><tr><td>5 mL Serological Pipette</td><td>Denville</td><td>P7127</td><td></td></tr><tr><td>10 mL Serological Pipette</td><td>Denville</td><td>P7128</td><td></td></tr><tr><td>25 mL Serological Pipette</td><td>Denville</td><td>P7129</td><td></td></tr><tr><td>1,000 mL PYREX Griffin Beaker</td><td>Fisher Scientific</td><td>02-540P</td><td></td></tr><tr><td>1,000 mL PYREX Reuasable Media Storage Bottle</td><td>Fisher Scientific</td><td>06-414-1D</td><td></td></tr><tr><td>1,000 mL graduated cylinder</td><td>Fisher Scientific</td><td>08-572-6G</td><td></td></tr><tr><td>SpectraMax 190</td><td>Molecular Devices</td><td></td><td>used to measure the Optical Density of cells</td></tr><tr><td>NanoDrop 2000</td><td>Thermo Scientific</td><td>ND-2000</td><td>Spectrophotometer used to quantify amount of DNA</td></tr><tr><td>Electronic UV transilluminator</td><td>Ultra Lum</td><td>MEB 20</td><td>used to visualize DNA in an Ethidium Bromide agarose gel</td></tr><tr><td>P1000 Gilson PIPETMAN</td><td>Fisher Scientific</td><td>F123602G</td><td></td></tr><tr><td>P200 Gilson PIPETMAN</td><td>Fisher Scientific</td><td>F123601G</td><td></td></tr><tr><td>P20 Gilson PIPETMAN</td><td>Fisher Scientific</td><td>F123600G</td><td></td></tr><tr><td>P10 Gilson PIPETMAN</td><td>Fisher Scientific</td><td>F144802G</td><td></td></tr><tr><td>1250 &amp;micro;L Low Retention Pipette Tips</td><td>GeneMate</td><td>P-1236-1250</td><td></td></tr><tr><td>200 &amp;micro;LLow Retention Pipette Tips</td><td>VWR</td><td>10017-044</td><td></td></tr><tr><td>10 &amp;micro;L XL Low Retention Pipette Tips</td><td>VWR</td><td>10017-042</td><td></td></tr><tr><td>50 mL conical tube</td><td>VWR</td><td>490001-627</td><td></td></tr><tr><td>15 mL conical tube</td><td>VWR</td><td>490001-621</td><td></td></tr><tr><td>cell scraper</td><td>Denville Scientific</td><td>TC9310</td><td></td></tr><tr><td>1.5 mL Microcentrifuge tubes</td><td>USA Scientific</td><td>1615-5500</td><td></td></tr><tr><td>HCl</td><td>Fluka Analytical</td><td>318949-1L</td><td></td></tr><tr><td>NaOH</td><td>J.T. Baker</td><td>5674-02</td><td></td></tr><tr><td>Wooden applicators</td><td>Solon Care</td><td>55900</td><td></td></tr><tr><td>Eppendorf microcentrifuge 5424</td><td>Fisher Scientific</td><td>05-400-005</td><td>microcentrifuge</td></tr><tr><td>Sorvall ST16R</td><td>Thermo Fisher Scientific</td><td>75004381</td><td>benchtop centrifuge</td></tr><tr><td>Amersham ECL Rabbit IgG, HRP-linked whole Ab (from donkey)</td><td>GE Healthcare</td><td>NA934-1ML</td><td>Secondary Antibody</td></tr><tr><td>Amersham ECL Mouse IgG, HRP-linked whole Ab (from sheep)</td><td>GE Healthcare</td><td>NA931-1ML</td><td>Secondary Antibody</td></tr><tr><td>SuperSignal West Pico Chemiluminescent Substrate</td><td>Thermo Fisher Scientific</td><td>34080</td><td>ECL detection solution</td></tr><tr><td>Isotemp Incubator</td><td>Thermo Fisher Scientific</td><td></td><td>Incubator</td></tr><tr><td>Mutitron 2</td><td>INFORS HT</td><td></td><td>Shaking incubator</td></tr><tr><td>Isotemp Digital-Control Water Bath Model 205</td><td>Fisher Scientific</td><td></td><td>water bath</td></tr><tr><td>Y2H mouse cDNA library in Y187 (pan tissue)</td><td>Clontech</td><td>630482</td><td>commercially available cDNA Library</td></tr><tr><td>Y2H mouse cDNA library in Y187 (mouse brain)</td><td>Clontech</td><td>630488</td><td>commercially available cDNA Library</td></tr><tr><td>pGADT7 AD Vector</td><td>Clontech</td><td>630442</td><td>commercially available AD Vector housing many cDNA libraries</td></tr><tr><td>pGBKT7 DNA-BD Vector</td><td>Clontech</td><td>630443</td><td>commercially available DNA-BD Vector</td></tr><tr><td>Biolase DNA Polymerase</td><td>Bioline</td><td>BIO-21042</td><td>DNA polymerase used for section 2.4</td></tr><tr><td>GeneMate GCL-60 Thermal Cycler</td><td>BioExpress</td><td>P-6050-60</td><td>pcr machine</td></tr><tr><td>TempAssure 0.5 mL PCR tubes</td><td>USA Scientific</td><td>1405-8100</td><td></td></tr></tbody></table>

a yeast 2-hybrid screen in batch to compare protein interactions

Screening for protein-protein interactions using the yeast 2-hybrid assay has long been an effective tool, but its use has largely been limited to the discovery of high-affinity interactors that are highly enriched in the library of interacting candidates. In a traditional format, the yeast 2-hybrid assay can yield too many colonies to analyze when conducted at low stringency where low affinity interactors might be found. Moreover, without a comprehensive and complete interrogation of the same library against different bait plasmids, a comparative analysis cannot be achieved. Although some of these problems can be addressed using arrayed prey libraries, the cost and infrastructure required to operate such screens can be prohibitive. As an alternative, we have adapted the yeast 2-hybrid assay to simultaneously uncover dozens of transient and static protein interactions within a single screen utilizing a strategy termed DEEPN (Dynamic Enrichment for Evaluation of Protein Networks), which incorporates high-throughput DNA sequencing and computation to follow the evolution of a population of plasmids that encode interacting partners. Here, we describe customized reagents and protocols that allow a DEEPN screen to be executed easily and cost-effectively.

The Y2H assay has been widely used for finding protein:protein interactions and several adaptations and systems have been developed. For the most part, the same considerations that help ensure success with these previous approaches are important for DEEPN. Some of the important benchmarks include: ensuring expression of DNA-binding domain fusion proteins, ensuring a low background of spurious His+ growth in the diploids containing the bait of interest with an empty prey plasmid, a high ma...

Watch this Scientific Journal Video about A Yeast 2-Hybrid Screen in Batch to Compare Protein Interactions at JoVE.com

A Yeast 2-Hybrid Screen in Batch to Compare Protein Interactions

Batch processing of yeast 2-hybrid screens allows for direct comparison of the interaction profiles of multiple bait proteins with a highly complex set of prey fusion proteins. Here, we describe refined methods, new reagents, and how to implement their use for such screens.

Screening for protein-protein interactions using the yeast 2-hybrid assay has long been an effective tool, but its use has largely been limited to the ...

a-yeast-2-hybrid-screen-in-batch-to-compare-protein-interactions

Research

JoVE Journal

Biochemistry

13.3K Views.  University of Iowa. Batch-verwerking van gist 2-hybrid schermen zorgt voor directe vergelijking van de profielen van de interactie van meerdere aas eiwitten met een zeer complexe verzameling prooi fusion eiwitten. We beschrijven hier, verfijnde methoden, nieuwe reagentia en het implementeren van het gebruik ervan voor dergelijke schermen.

Video: A Yeast 2-Hybrid Screen in Batch to Compare Protein Interactions

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 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 ...

Informatic Analysis of Sequence Data from Batch Yeast 2-Hybrid Screens

We have adapted the yeast 2-hybrid assay to simultaneously uncover dozens of transient and static protein interactions within a single screen utilizing high-throughput short-read DNA sequencing. The resulting sequence datasets can not only track what genes in a population that are enriched during selection for positive yeast 2-hybrid interactions, but also give detailed information about the relevant subdomains of proteins sufficient for interaction. Here, we describe a full suite of stand-alone software programs that allow non-experts to perform all the bioinformatics and statistical steps to process and analyze DNA sequence fastq files from a batch yeast 2-hybrid assay. The processing steps covered by these software include: 1) mapping and counting sequence reads corresponding to each candidate protein encoded within a yeast 2-hybrid prey library; 2) a statistical analysis program that evaluates the enrichment profiles; and 3) tools to examine the translational frame and position within the coding region of each enriched plasmid that encodes the interacting proteins of interest.

Deep sequencing of yeast populations selected for positive yeast 2-hybrid interactions potentially yields a wealth of information about interacting partner proteins. Here, we describe the operation of specific bioinformatics tools and customized updated software to analyze sequence data from such screens.

We have adapted the yeast 2-hybrid assay to simultaneously uncover dozens of transient and static protein interactions within a single screen utilizing ...

Genetics

A Comparative Approach to Characterize the Landscape of Host-Pathogen Protein-Protein Interactions

Significant efforts were gathered to generate large-scale comprehensive protein-protein interaction network maps. This is instrumental to understand the pathogen-host relationships and was essentially performed by genetic screenings in yeast two-hybrid systems. The recent improvement of protein-protein interaction detection by a Gaussia luciferase-based fragment complementation assay now offers the opportunity to develop integrative comparative interactomic approaches necessary to rigorously compare interaction profiles of proteins from different pathogen strain variants against a common set of cellular factors.
This paper specifically focuses on the utility of combining two orthogonal methods to generate protein-protein interaction datasets: yeast two-hybrid (Y2H) and a new assay, high-throughput Gaussia princeps protein complementation assay (HT-GPCA) performed in mammalian cells.
A large-scale identification of cellular partners of a pathogen protein is performed by mating-based yeast two-hybrid screenings of cDNA libraries using multiple pathogen strain variants. A subset of interacting partners selected on a high-confidence statistical scoring is further validated in mammalian cells for pair-wise interactions with the whole set of pathogen variants proteins using HT-GPCA. This combination of two complementary methods improves the robustness of the interaction dataset, and allows the performance of a stringent comparative interaction analysis. Such comparative interactomics constitute a reliable and powerful strategy to decipher any pathogen-host interplays.

This article focuses on the identification of high-confident interaction datasets between host and pathogen proteins using a combination of two orthogonal methods: yeast two-hybrid followed by a high-throughput interaction assay in mammalian cells called HT-GPCA.

Significant efforts were gathered to generate  large-scale comprehensive protein-protein interaction network maps. This is  instrumental to understand the ...

Immunology and Infection

Split-Ubiquitin Based Membrane Yeast Two-Hybrid (MYTH) System: A Powerful Tool For Identifying Protein-Protein Interactions

The fundamental biological and clinical importance of integral membrane proteins prompted the development of a yeast-based system for the high-throughput identification of protein-protein interactions (PPI) for full-length transmembrane proteins. To this end, our lab developed the split-ubiquitin based Membrane Yeast Two-Hybrid (MYTH) system. This technology allows for the sensitive detection of transient and stable protein interactions using Saccharomyces cerevisiae as a host organism. MYTH takes advantage of the observation that ubiquitin can be separated into two stable moieties: the C-terminal half of yeast ubiquitin (Cub) and the N-terminal half of the ubiquitin moiety (Nub). In MYTH, this principle is adapted for use as a 'sensor' of protein-protein interactions. Briefly, the integral membrane bait protein is fused to Cub which is linked to an artificial transcription factor. Prey proteins, either in individual or library format, are fused to the Nub moiety. Protein interaction between the bait and prey leads to reconstitution of the ubiquitin moieties, forming a full-length 'pseudo-ubiquitin' molecule. This molecule is in turn recognized by cytosolic deubiquitinating enzymes, resulting in cleavage of the transcription factor, and subsequent induction of reporter gene expression. The system is highly adaptable, and is particularly well-suited to high-throughput screening. It has been successfully employed to investigate interactions using integral membrane proteins from both yeast and other organisms.

Split-Ubiquitin Based Membrane Yeast Two-Hybrid MYTH System: A Powerful Tool For Identifying Protein-Protein Interactions

MYTH allows the sensitive detection of transient and stable interactions between proteins that are expressed in the model organism Saccharomyces cerevisiae. It has been successfully applied to study exogenous and yeast integral membrane proteins in order to identify their interacting partners in a high throughput manner.

The fundamental biological and clinical importance of integral membrane proteins prompted the development of a yeast-based system for the high-throughput ...

Biology

Pulldown Assay Coupled with Co-Expression in Bacteria Cells as a Time-Efficient Tool for Testing Challenging Protein-Protein Interactions

Pulldown is an easy and widely used protein-protein interaction assay. However, it has limitations in studying protein complexes that do not assemble effectively in vitro. Such complexes may require co-translational assembly and the presence of molecular chaperones; either they form stable oligomers which cannot dissociate and re-associate in vitro or are unstable without a binding partner. To overcome these problems, it is possible to use a method based on the bacterial co-expression of differentially tagged proteins using a set of compatible vectors followed by the conventional pulldown techniques. The workflow is more time-efficient compared to traditional pulldown because it lacks the time-consuming steps of separate purification of interacting proteins and their following incubation. Another advantage is a higher reproducibility due to a significantly smaller number of steps and a shorter period of time in which proteins that exist within the in vitro environment are exposed to proteolysis and oxidation. The method was successfully applied for studying a number of protein-protein interactions when other in vitro techniques were found to be unsuitable. The method can be used for batch testing protein-protein interactions. Representative results are shown for studies of interactions between BTB domain and intrinsically disordered proteins, and of heterodimers of zinc-finger-associated domains.

Here, we describe a method for the bacterial co-expression of differentially tagged proteins using a set of compatible vectors, followed by the conventional pulldown techniques to study protein complexes that cannot assemble in vitro.

Pulldown is an easy and widely used protein-protein interaction assay. However, it has limitations in studying protein complexes that do not assemble ...

Unravelling the Function of a Bacterial Effector from a Non-cultivable Plant Pathogen Using a Yeast Two-hybrid Screen

Unravelling the molecular mechanisms of disease manifestations is important to understand pathologies and symptom development in plant science. Bacteria have evolved different strategies to manipulate their host metabolism for their own benefit. This bacterial manipulation is often coupled with severe symptom development or the death of the affected plants. Determining the specific bacterial molecules responsible for the host manipulation has become an important field in microbiological research. After the identification of these bacterial molecules, called &#34;effectors,&#34; it is important to elucidate their function. A straightforward approach to determine the function of an effector is to identify its proteinaceous binding partner in its natural host via a yeast two-hybrid (Y2H) screen. Normally the host harbors numerous potential binding partners that cannot be predicted sufficiently by any in silico algorithm. It is thus the best choice to perform a screen with the hypothetical effector against a whole library of expressed host proteins. It is especially challenging if the causative agent is uncultivable like phytoplasma. This protocol provides step-by-step instructions for DNA purification from a phytoplasma-infected woody host plant, the amplification of the potential effector, and the subsequent identification of the plant&#39;s molecular interaction partner with a Y2H screen. Even though Y2H screens are commonly used, there is a trend to outsource this technique to biotech companies that offer the Y2H service at a cost. This protocol provides instructions on how to perform a Y2H in any decently equipped molecular biology laboratory using standard lab techniques.

Bacterial effector proteins are important for establishing successful infections. This protocol describes the experimental identification of proteinaceous binding partners of a bacterial effector protein in its natural plant host. Identifying these effector interactions via yeast two-hybrid screens has become an important tool in unravelling molecular pathogenicity strategies.

Unravelling the molecular mechanisms of disease manifestations is important to understand pathologies and symptom development in plant science. Bacteria ...

Modified Yeast-Two-Hybrid System to Identify Proteins Interacting with the Growth Factor Progranulin

Progranulin (PGRN), also known as granulin epithelin precursor (GEP), is a 593-amino-acid autocrine growth factor. PGRN is known to play a critical role in a variety of physiologic and disease processes, including early embryogenesis, wound healing 1, inflammation 2, 3, and host defense 4. PGRN also functions as a neurotrophic factor 5, and mutations in the PGRN gene resulting in partial loss of the PGRN protein cause frontotemporal dementia 6, 7. Our recent studies have led to the isolation of PGRN as an important regulator of cartilage development and degradation 8-11. Although PGRN, discovered nearly two decades ago, plays crucial roles in multiple physiological and pathological conditions, efforts to exploit the actions of PGRN and understand the mechanisms involved have been significantly hampered by our inability to identify its binding receptor(s). To address this issue, we developed a modified yeast two-hybrid (MY2H) approach based on the most commonly used GAL4 based 2-hybrid system. Compared with the conventional yeast two-hybrid screen, MY2H dramatically shortens the screen process and reduces the number of false positive clones. In addition, this approach is reproducible and reliable, and we have successfully employed this system in isolating the binding proteins of various baits, including ion channel 12, extracellular matrix protein 10, 13, and growth factor14. In this paper, we describe this MY2H experimental procedure in detail using PGRN as an example that led to the identification of TNFR2 as the first known PGRN-associated receptor 14, 15.

We have modified the conventional yeast two-hybrid screening, an effective genetic tool in identifying protein interaction. This modification markedly shortens the process, reduces the workload, and most importantly, reduces the number of false positives. In addition, this approach is reproducible and reliable.

Progranulin (PGRN), also known as granulin epithelin precursor (GEP), is a 593-amino-acid autocrine growth factor. PGRN is known to play a critical role ...

Probing High-density Functional Protein Microarrays to Detect Protein-protein Interactions

High-density functional protein microarrays containing ~4,200 recombinant yeast proteins are examined for kinase protein-protein interactions using an affinity purified yeast kinase fusion protein containing a V5-epitope tag for read-out. Purified kinase is obtained through culture of a yeast strain optimized for high copy protein production harboring a plasmid containing a Kinase-V5 fusion construct under a GAL inducible promoter. The yeast is grown in restrictive media with a neutral carbon source for 6 hr followed by induction with 2% galactose. Next, the culture is harvested and kinase is purified using standard affinity chromatographic techniques to obtain a highly purified protein kinase for use in the assay. The purified kinase is diluted with kinase buffer to an appropriate range for the assay and the protein microarrays are blocked prior to hybridization with the protein microarray. After the hybridization, the arrays are probed with monoclonal V5 antibody to identify proteins bound by the kinase-V5 protein. Finally, the arrays are scanned using a standard microarray scanner, and data is extracted for downstream informatics analysis1,2 to determine a high confidence set of protein interactions for downstream validation in vivo.

Using protein microarrays containing nearly the entire S. cerevisiae proteome is probed for rapid unbiased interrogation of thousands of protein-protein interactions in parallel. This method can be utilized for protein-small molecule, posttranslational modification, and other assays in high-throughput.

High-density functional protein microarrays containing ~4,200 recombinant yeast proteins are examined for kinase protein-protein interactions using an ...

Biomolecular Interaction Studies Using Yeast Two-Hybrid Technique 

Isolating Interaction-Null&#47;Impaired Mutants Using the Yeast Two-Hybrid Assay

Protein-protein interactions are one of the most basic processes that underlie biological phenomena. One of the simplest and best ways to understand the role(s) and function(s) of a specific protein-protein interaction is to compare the phenotype of the wild-type (with the relevant protein-protein interaction) and those of mutants that lack the relevant interaction. Therefore, if such mutants can be isolated, they will help to elucidate the related biological processes. The yeast two-hybrid (Y2H) procedure is a powerful approach not only to detect protein-protein interactions but also to isolate interaction-null/impaired mutants. In this article, a protocol is presented to isolate interaction-null/impaired mutants using Y2H technology. First, a mutation library is constructed by combining the polymerase chain reaction and efficient seamless cloning technology, which efficiently excludes the empty vector from the library. Second, interaction-null/impaired mutants are screened by the Y2H assay. Because of a trick in the Y2H vector, undesired mutants, such as those with frameshift and nonsense mutations, are efficiently eliminated from the screening process. This strategy is simple and can, therefore, be applied to any combination of proteins whose interaction can be detected by the two-hybrid system.

Author Spotlight: Enhanced Isolation of Interaction-Null Mutants in Yeast

The interactions of biomolecules, such as protein-protein interactions, are the molecular basis of biological functions. If interaction-null/impaired mutants that specifically lack the relevant interaction can be isolated, they will greatly help to understand the function(s) of this interaction. This article presents an efficient way to isolate interaction-null/impaired mutants.

Protein-protein interactions are one of the most basic processes that underlie biological phenomena. One of the simplest and best ways to understand the ...

Yeast Two-Hybrid Assay to Determine Protein Self-Association in Yeast Cells

In this yeast two-hybrid assay, yeast cells in mid-log phase are used for transformation. Harvest the cells by centrifugation. Resuspend each pellet in five milliliters of sterile water, and pool the cell suspensions. Centrifuge the cell suspension.
After discarding the supernatant, resuspend the yeast pellet in one milliliter of freshly-prepared sterile 1X lithium acetate and TE. The competent yeast cells must be used within one hour of preparation. Prepare plasmid samples by mixing bait and target plasmid DNA with 100 micrograms of Herring testes carrier DNA.
To each 1.5-milliliter tube, add 100 microliters of the competent yeast suspension and 600 microliters of 1X lithium acetate and PEG solution, and vortex for about 30 seconds. Incubate at 30 degrees Celsius for 30 minutes with shaking. Add 80 microliters of dimethyl sulfoxide, and mix well by gentle inversion.
Heat shock for 15 minutes in a 42-degree Celsius water bath while mixing every two to three minutes. Chill the cell suspension on ice for two minutes, and then, centrifuge to recover the yeast. Resuspend each cell pellet in 100 microliters of 1X TE. Plate the cells on appropriate minimal SD medium plates to keep selective pressure on both bait and target plasmids. Incubate the plates upside down at 30 degrees Celsius for four to five days.
The yeast colonies are ready for this assay when they are about two millimeters in diameter. Pipette 2.5 milliliters of freshly-prepared Z-Buffer and X-Gal solution to a clean 100-millimeter plate and place a cellulose filter paper in the plate. Place a new filter paper over the surface of the plate with the yeast colonies to be assayed. Use forceps to gently rub the filter paper onto the plate and leave for approximately five minutes for the colonies to attach.
While using appropriate personal protective equipment, carefully lift the filter paper and submerge it into a pool of liquid nitrogen for 30 seconds. Let the frozen filter paper thaw at room temperature for two minutes. Place the filter paper with the colony side up on top of the pre-soaked filter paper inside the 100-millimeter plate and incubate at 30 degrees Celsius until blue colonies appear.

A Yeast 2-Hybrid Screen in Batch to Compare Protein Interactions

Samenvatting

Meer video's verkennen

Hoofdstukken in deze video