Difference between revisions of "Part:BBa K5237004"
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__NOTOC__ | __NOTOC__ | ||
− | <partinfo> | + | <partinfo>BBa_K5237004</partinfo> |
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<section id="1"> | <section id="1"> | ||
<h1>Half-Staple: Oct1-DBD</h1> | <h1>Half-Staple: Oct1-DBD</h1> | ||
− | <p>Oct1-DBD is the DNA-binding domain of the human Oct1 transcription factor, | + | <p>Oct1-DBD is the DNA-binding domain of the human Oct1 transcription factor, it can be readily fused with other |
− | + | DNA-bindig proteins to form a functional staple for DNA-DNA proximity. We used this part as a component for our Simple | |
+ | staple (<a href=https://parts.igem.org/Part:BBa_K5237006 target="_blank">BBa_K5237006</a>) resulting in a bivalent DNA | ||
+ | binding staple, and also fused to mNeonGreen, as part of a FRET readout system (<a | ||
+ | href=https://parts.igem.org/Part:BBa_K5237016 target="_blank">BBa_K5237016</a>). | ||
+ | </p> | ||
+ | |||
<p> </p> | <p> </p> | ||
</section> | </section> | ||
Line 69: | Line 74: | ||
<section> | <section> | ||
<font size="5"><b>The PICasSO Toolbox </b> </font> | <font size="5"><b>The PICasSO Toolbox </b> </font> | ||
+ | <p><br></p> | ||
+ | <div class="thumb"></div> | ||
+ | <div class="thumbinner" style="width:550px"><img alt="" src="https://static.igem.wiki/teams/5237/wetlab-results/registry-part-collection-engineering-cycle-example-overview.svg" style="width:99%;" class="thumbimage"> | ||
+ | <div class="thumbcaption"> | ||
+ | <i><b>Figure 1: Example how the part collection can be used to engineer new staples</b></i> | ||
+ | </div> | ||
+ | </div> | ||
+ | </div> | ||
+ | |||
− | <p>The 3D organization of the genome plays a crucial role in regulating gene expression in eukaryotic cells, | + | <p> |
+ | <br> | ||
+ | The 3D organization of the genome plays a crucial role in regulating gene expression in eukaryotic cells, | ||
impacting cellular behavior, evolution, and disease. Beyond the linear DNA sequence, the spatial arrangement of | impacting cellular behavior, evolution, and disease. Beyond the linear DNA sequence, the spatial arrangement of | ||
− | chromatin, influenced by DNA-DNA interactions, shapes pathways of gene regulation. However, tools to precisely | + | chromatin, influenced by DNA-DNA interactions, shapes pathways of gene regulation. However, the tools to precisely |
− | manipulate this genomic architecture remain limited, | + | manipulate this genomic architecture remain limited, rendering it challenging to explore the full potential of the |
− | genome in synthetic biology. | + | 3D genome in synthetic biology. We - iGEM Team Heidelberg 2024 - have developed PICasSO, a powerful molecular |
+ | toolbox based on various DNA-binding proteins to address this issue. | ||
+ | |||
</p> | </p> | ||
− | <p>The <b>PICasSO | + | <p> |
− | + | The <b>PICasSO</b> part collection offers a comprehensive, modular platform for precise manipulation and | |
− | + | re-programming | |
− | + | of DNA-DNA interactions using protein staples in living cells, enabling researchers to recreate natural 3D genomic | |
− | + | interactions, such as enhancer hijacking, or to design entirely new spatial architectures for gene regulation. | |
+ | Beyond its versatility, PICasSO includes robust assay systems to support the engineering, optimization, and | ||
+ | testing of new staples, ensuring functionality <i>in vitro</i> and <i>in vivo</i>. We took special care to include | ||
+ | parts crucial for testing every step of the cycle (design, build, test, learn) when engineering new parts | ||
+ | </p> | ||
+ | |||
+ | <p>At its heart, the PICasSO part collection consists of three categories. <br><b>(i)</b> Our <b>DNA-binding proteins</b> | ||
+ | include our | ||
+ | finalized enhancer hijacking Cas staple as well as half staples that can be used by scientists to compose entirely | ||
+ | new Cas staples in the future. We also include our simple staples that serve as controls for successful stapling | ||
+ | and can be further engineered to create alternative, simpler and more compact staples. <br> | ||
+ | <b>(ii)</b> As <b>functional elements</b>, we list additional parts that enhance the functionality of our Cas and Basic staples. These | ||
+ | consist of | ||
+ | protease-cleavable peptide linkers and inteins that allow condition-specific, dynamic stapling <i>in vivo</i>. | ||
+ | Besides staple functionality, we also include the parts to enable the efficient delivery of PICasSO's constructs with our | ||
+ | interkingdom conjugation system. <br> | ||
+ | <b>(iii)</b> As the final component of our collection, we provide parts that support the use of our <b>custom readout | ||
+ | systems</b>. These include components of our established FRET-based proximity assay system, enabling users to | ||
+ | confirm | ||
+ | accurate stapling. Additionally, we offer a complementary, application-oriented testing system for functional | ||
+ | readout via a luciferase reporter, which allows for straightforward experimental simulation of enhancer hijacking. | ||
</p> | </p> | ||
− | |||
− | |||
− | |||
− | |||
<p> | <p> | ||
− | + | The following table gives a complete overview of all parts in our PICasSO toolbox. The highlighted parts showed | |
+ | exceptional performance as described on our iGEM wiki and can serve as a reference. The other parts in the | ||
+ | collection are versatile building blocks designed to provide future iGEMers with the flexibility to engineer their | ||
+ | own custom Cas staples, enabling further optimization and innovation.<br> | ||
</p> | </p> | ||
− | <table style="width: | + | <p> |
− | <td colspan=" | + | <font size="4"><b>Our part collection includes:</b></font><br> |
+ | </p> | ||
+ | |||
+ | <table style="width: 90%;"> | ||
+ | <td colspan="3" align="left"><b>DNA-binding proteins: </b> | ||
The building blocks for engineering of custom staples for DNA-DNA interactions with a modular system ensuring | The building blocks for engineering of custom staples for DNA-DNA interactions with a modular system ensuring | ||
easy assembly.</td> | easy assembly.</td> | ||
<tbody> | <tbody> | ||
− | <tr | + | <tr bgcolor="#FFD700"> |
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237000" target="_blank">BBa_K5237000</a></td> |
<td>fgRNA Entryvector MbCas12a-SpCas9</td> | <td>fgRNA Entryvector MbCas12a-SpCas9</td> | ||
+ | <td>Entryvector for simple fgRNA cloning via SapI</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237001" target="_blank">BBa_K5237001</a></td> |
− | <td> | + | <td>Staple subunit: dMbCas12a-Nucleoplasmin NLS</td> |
+ | <td>Staple subunit that can be combined to form a functional staple, for example with fgRNA and dCas9 </td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237002" target="_blank">BBa_K5237002</a></td> |
− | <td> | + | <td>Staple subunit: SV40 NLS-dSpCas9-SV40 NLS</td> |
+ | <td>Staple subunit that can be combined to form a functional staple, for example with our fgRNA or dCas12a | ||
+ | </td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237003" target="_blank">BBa_K5237003</a></td> |
<td>Cas-Staple: SV40 NLS-dMbCas12a-dSpCas9-Nucleoplasmin NLS</td> | <td>Cas-Staple: SV40 NLS-dMbCas12a-dSpCas9-Nucleoplasmin NLS</td> | ||
+ | <td>Functional Cas staple that can be combined with sgRNA or fgRNA to bring two DNA strands in close proximity | ||
+ | </td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237004" target="_blank">BBa_K5237004</a></td> |
− | <td> | + | <td>Staple subunit: Oct1-DBD</td> |
+ | <td>Staple subunit that can be combined to form a functional staple, for example with TetR.<br> | ||
+ | Can also be combined with a fluorescent protein as part of the FRET proximity assay</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237005" target="_blank">BBa_K5237005</a></td> |
− | <td> | + | <td>Staple subunit: TetR</td> |
+ | <td>Staple subunit that can be combined to form a functional staple, for example with Oct1.<br> | ||
+ | Can also be combined with a fluorescent protein as part of the FRET proximity assay</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237006" target="_blank">BBa_K5237006</a></td> |
− | <td>Simple | + | <td>Simple taple: TetR-Oct1</td> |
+ | <td>Functional staple that can be used to bring two DNA strands in close proximity</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237007" target="_blank">BBa_K5237007</a></td> |
− | <td> | + | <td>Staple subunit: GCN4</td> |
+ | <td>Staple subunit that can be combined to form a functional staple, for example with rGCN4</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237008" target="_blank">BBa_K5237008</a></td> |
− | <td> | + | <td>Staple subunit: rGCN4</td> |
+ | <td>Staple subunit that can be combined to form a functional staple, for example with rGCN4</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237009" target="_blank">BBa_K5237009</a></td> |
− | <td>Mini | + | <td>Mini staple: bGCN4</td> |
+ | <td> | ||
+ | Assembled staple with minimal size that can be further engineered</td> | ||
</tr> | </tr> | ||
</tbody> | </tbody> | ||
− | <td colspan=" | + | <td colspan="3" align="left"><b>Functional elements: </b> |
Protease cleavable peptide linkers and inteins are used to control and modify staples for further optimization | Protease cleavable peptide linkers and inteins are used to control and modify staples for further optimization | ||
for custom applications.</td> | for custom applications.</td> | ||
<tbody> | <tbody> | ||
<tr bgcolor="#FFD700"> | <tr bgcolor="#FFD700"> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237010" target="_blank">BBa_K5237010</a></td> |
<td>Cathepsin B-Cleavable Linker (GFLG)</td> | <td>Cathepsin B-Cleavable Linker (GFLG)</td> | ||
+ | <td>Cathepsin B cleavable peptide linker, that can be used to combine two staple subunits ,to make responsive | ||
+ | staples</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237011" target="_blank">BBa_K5237011</a></td> |
<td>Cathepsin B Expression Cassette</td> | <td>Cathepsin B Expression Cassette</td> | ||
+ | <td>Cathepsin B which can be selectively express to cut the cleavable linker</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237012" target="_blank">BBa_K5237012</a></td> |
<td>Caged NpuN Intein</td> | <td>Caged NpuN Intein</td> | ||
+ | <td>Undergoes protein transsplicing after protease activation, can be used to create functionalized staple | ||
+ | units</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237013" target="_blank">BBa_K5237013</a></td> |
<td>Caged NpuC Intein</td> | <td>Caged NpuC Intein</td> | ||
+ | <td>Undergoes protein transsplicing after protease activation, can be used to create functionalized staple | ||
+ | units</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237014" target="_blank">BBa_K5237014</a></td> |
<td>fgRNA processing casette</td> | <td>fgRNA processing casette</td> | ||
+ | <td>Processing casette to produce multiple fgRNAs from one transcript, can be used for multiplexing</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237015" target="_blank">BBa_K5237015</a></td> |
<td>Intimin anti-EGFR Nanobody</td> | <td>Intimin anti-EGFR Nanobody</td> | ||
+ | <td>Interkindom conjugation between bacteria and mammalian cells, as alternative delivery tool for large | ||
+ | constructs</td> | ||
</tr> | </tr> | ||
</tbody> | </tbody> | ||
− | <td colspan=" | + | <td colspan="3" align="left"><b>Readout Systems: </b> |
FRET and enhancer recruitment to measure proximity of stapled DNA in bacterial and mammalian living cells | FRET and enhancer recruitment to measure proximity of stapled DNA in bacterial and mammalian living cells | ||
enabling swift testing and easy development for new systems.</td> | enabling swift testing and easy development for new systems.</td> | ||
<tbody> | <tbody> | ||
<tr bgcolor="#FFD700"> | <tr bgcolor="#FFD700"> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K52370016" target="_blank">BBa_K5237016</a></td> |
<td>FRET-Donor: mNeonGreen-Oct1</td> | <td>FRET-Donor: mNeonGreen-Oct1</td> | ||
+ | <td>Donor part for the FRET assay binding the Oct1 binding cassette. Can be used to visualize DNA-DNA | ||
+ | proximity</td> | ||
</tr> | </tr> | ||
<tr bgcolor="#FFD700"> | <tr bgcolor="#FFD700"> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237017" target="_blank">BBa_K5237017</a></td> |
<td>FRET-Acceptor: TetR-mScarlet-I</td> | <td>FRET-Acceptor: TetR-mScarlet-I</td> | ||
+ | <td>Acceptor part for the FRET assay binding the TetR binding cassette. Can be used to visualize DNA-DNA | ||
+ | proximity</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237018" target="_blank">BBa_K5237018</a></td> |
<td>Oct1 Binding Casette</td> | <td>Oct1 Binding Casette</td> | ||
+ | <td>DNA sequence containing 12 Oct1 binding motifs, can be used for different assays such as the FRET | ||
+ | proximity assay</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237019" target="_blank">BBa_K5237019</a></td> |
<td>TetR Binding Cassette</td> | <td>TetR Binding Cassette</td> | ||
+ | <td>DNA sequence containing 12 Oct1 binding motifs, can be used for different assays such as the FRET | ||
+ | proximity assay</td> | ||
</tr> | </tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237020" target="_blank">BBa_K5237020</a></td> |
<td>Cathepsin B-Cleavable Trans-Activator: NLS-Gal4-GFLG-VP64</td> | <td>Cathepsin B-Cleavable Trans-Activator: NLS-Gal4-GFLG-VP64</td> | ||
+ | <td>Readout system that responds to protease activity. It was used to test Cathepsin-B cleavable linker.</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237021" target="_blank">BBa_K5237021</a></td> |
<td>NLS-Gal4-VP64</td> | <td>NLS-Gal4-VP64</td> | ||
+ | <td>Trans-activating enhancer, that can be used to simulate enhancer hijacking. </td> | ||
</tr> | </tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237022" target="_blank">BBa_K5237022</a></td> |
<td>mCherry Expression Cassette: UAS, minimal Promotor, mCherry</td> | <td>mCherry Expression Cassette: UAS, minimal Promotor, mCherry</td> | ||
+ | <td>Readout system for enhancer binding. It was used to test Cathepsin-B cleavable linker.</td> | ||
</tr> | </tr> | ||
<tr> | <tr> | ||
− | <td><a href="https://parts.igem.org/Part: | + | <td><a href="https://parts.igem.org/Part:BBa_K5237023" target="_blank">BBa_K5237023</a></td> |
− | <td>UAS binding Firefly | + | <td>Oct1 - 5x UAS binding casette</td> |
+ | <td>Oct1 and UAS binding cassette, that was used for the simulated enhancer hijacking assay.</td> | ||
+ | </tr> | ||
+ | <tr> | ||
+ | <td><a href="https://parts.igem.org/Part:BBa_K5237024" target="_blank">BBa_K5237024</a></td> | ||
+ | <td>TRE-minimal promoter- firefly luciferase</td> | ||
+ | <td>Contains Firefly luciferase controlled by a minimal promoter. It was used as a luminescence readout for | ||
+ | simulated enhancer hijacking.</td> | ||
</tr> | </tr> | ||
− | |||
</tbody> | </tbody> | ||
</table> | </table> | ||
Line 212: | Line 295: | ||
<!--################################--> | <!--################################--> | ||
<span class='h3bb'>Sequence and Features</span> | <span class='h3bb'>Sequence and Features</span> | ||
− | <partinfo> | + | <partinfo>BBa_K5237004 SequenceAndFeatures</partinfo> |
<!--################################--> | <!--################################--> | ||
Line 223: | Line 306: | ||
<p>Oct1-DBD is the DNA-binding domain of the human transcription factor Oct1 (POU2F1), which plays a key role in | <p>Oct1-DBD is the DNA-binding domain of the human transcription factor Oct1 (POU2F1), which plays a key role in | ||
gene regulation, immune response, and stress adaptation in eukaryotic cells. This domain specifically binds to the | gene regulation, immune response, and stress adaptation in eukaryotic cells. This domain specifically binds to the | ||
− | octamer motif ( | + | octamer motif (5'-ATGCAAAT-3') within promoter and enhancer regions, influencing transcriptional activity |
(Lundbäck <i>et al.</i>, 2000). The Oct1-DBD consists of both a POU-specific domain and a POU homeodomain, which | (Lundbäck <i>et al.</i>, 2000). The Oct1-DBD consists of both a POU-specific domain and a POU homeodomain, which | ||
work | work | ||
Line 229: | Line 312: | ||
</p> | </p> | ||
<p>In synthetic biology, Oct1-DBD was previously used for plasmid display technology due to its strong binding | <p>In synthetic biology, Oct1-DBD was previously used for plasmid display technology due to its strong binding | ||
− | affinity (K<sub>D</sub> = 9 × | + | affinity (K<sub>D</sub> = 9 × 10<sup>-11</sup> M). Proteins fused with Oct1-DBD showed increased expression |
and protein solubility | and protein solubility | ||
(Parker <i>et al.</i> 2020). | (Parker <i>et al.</i> 2020). | ||
Line 239: | Line 322: | ||
target="_blank">BBa_K5237016</a>). | target="_blank">BBa_K5237016</a>). | ||
</p> | </p> | ||
− | |||
− | |||
</section> | </section> | ||
<section id="3"> | <section id="3"> | ||
Line 253: | Line 334: | ||
<section id="4"> | <section id="4"> | ||
<h1>4. Results</h1> | <h1>4. Results</h1> | ||
− | <p>Oct1 was N-terminally fused to the His6-mNeonGreen | + | <p>Oct1 was N-terminally fused to the His6-mNeonGreen. The fusion protein was expressed from a T7 based expression |
− | purified using metal affinity chromatography with Ni-NTA beads.(Figure | + | plasmid and subsequently |
+ | purified using metal affinity chromatography with Ni-NTA beads.(Figure 2, left) | ||
DNA binding affinity was estimated with an electrophoretic mobility shift assay (EMSA). For this, three different | DNA binding affinity was estimated with an electrophoretic mobility shift assay (EMSA). For this, three different | ||
buffer conditions were tested (Binding buffer 1: 137 mM NaCl, 2.7 mM KCl, 10 mM Na<sub>2</sub>HPO<sub>4</sub>, 1.8 | buffer conditions were tested (Binding buffer 1: 137 mM NaCl, 2.7 mM KCl, 10 mM Na<sub>2</sub>HPO<sub>4</sub>, 1.8 | ||
Line 260: | Line 342: | ||
0.1 % (v/v) IGEPAL® CA-360, 1 mM EDTA; Binding buffer 2: 10 mM Tris, 50 mM KCl; NaP250: | 0.1 % (v/v) IGEPAL® CA-360, 1 mM EDTA; Binding buffer 2: 10 mM Tris, 50 mM KCl; NaP250: | ||
Na<sub>2</sub>HPO<sub>4</sub>, 150 mM | Na<sub>2</sub>HPO<sub>4</sub>, 150 mM | ||
− | NaCl, 250 mM Imidazol). DNA binding could only be detected for Binding buffer 1. (Figure | + | NaCl, 250 mM Imidazol). DNA binding could only be detected for Binding buffer 1. (Figure 2, right) |
</p> | </p> | ||
<div class="thumb"> | <div class="thumb"> | ||
− | <div class="thumbinner" style="display: flex; justify-content: center;"> | + | <div class="thumbinner" styl="width:60%;"> |
− | + | <div style="display: flex; justify-content: center; border:none;"> | |
− | + | <div> | |
− | + | <a href="Fig2_left"> | |
− | + | <img alt="" src="https://static.igem.wiki/teams/5237/wetlab-results/sds-page-mng-oct1-expression.svg" | |
− | </a> | + | style="height: 350px; width: auto; border:none;" class="thumbimage"> |
+ | </a> | ||
+ | </div> | ||
+ | <div> | ||
+ | <a href="Fig2_right"> | ||
+ | <img alt="" | ||
+ | src="https://static.igem.wiki/teams/5237/wetlab-results/emsa-oct1-binding-buffer-optimization.svg" | ||
+ | style="height: 350px; width: auto; border:none;" class="thumbimage"> | ||
+ | </a> | ||
+ | </div> | ||
</div> | </div> | ||
− | <div | + | <div class="thumbcaption" style="text-align: justify;"> |
− | + | <i><b>Figure 3: Expression and DNA binding analysis of His<sub>6</sub>-mNeonGreen-Oct1-DBD.</i></b><br> | |
− | + | <i><b>Left image:</b>Lane 1: raw lysate of E. coli expression culture after steril-filtration; Lane 2: Flow | |
− | + | through of first wash | |
− | + | (10 bed volumes of NaP10 (Na<sub>2</sub>HPO<sub>4</sub>, 150 mM NaCl, 10 mM Imidazol)); Lane 3: Flow through | |
− | + | of | |
+ | second wash (10 bed volumes of NaP20 (Na<sub>2</sub>HPO<sub>4</sub>, 150 mM NaCl, 20 mM Imidazol)); Lane 4: | ||
+ | Elution of purified protein.<br> | ||
+ | 1 µL of each fraction was loaded after mixing and heating with 4x Laeemli buffer, on a 4-15% TGX-Gel. The | ||
+ | expected band size of the protein is 56 840.23 Da, highlighted in red on the gel.<br> | ||
+ | <b>Right image</b> Purified mNeonGreen-Oct1 fusion-protein (1000 nM, 100 nM or 10 nM) were equilibrated with 0.5 µM DNA, | ||
+ | containing three Oct1 binding sites, in different buffer compositions. | ||
+ | (Binding buffer 1: 137 mM NaCl, 2.7 mM KCl, 10 mM Na 2HPO4, 1.8 mM KH2HPO4, 0.1 % (v/v) IGEPAL® CA-360, 1 mM | ||
+ | EDTA; Binding buffer 2: 10 mM Tris, 50 mM KCl; NaP250: 50 mM NaH2PO4, 150 mM NaCl, 250 mM Imidazol) Bands were visualized with SYBR-Safe staining.</i> | ||
</div> | </div> | ||
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− | <p> | + | <p>Lundbäck, T., Chang, J.-F., Phillips, K., Luisi, B., & Ladbury, J. E. (2000). Characterization of Sequence-Specific DNA Binding by the Transcription Factor Oct-1. <em>Biochemistry, 39</em>(25), 7570–7579. <a href="https://doi.org/10.1021/bi000377h" target="_blank">https://doi.org/10.1021/bi000377h</a></p> |
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− | + | <p>Park, J. H., Kwon, H. W., & Jeong, K. J. (2013). Development of a plasmid display system with an Oct-1 DNA-binding domain suitable for in vitro screening of engineered proteins. <em>Journal of Bioscience and Bioengineering, 116</em>(2), 246–252. <a href="https://doi.org/10.1016/j.jbiosc.2013.02.005" target="_blank">https://doi.org/10.1016/j.jbiosc.2013.02.005</a></p> | |
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− | + | <p>Park, Y., Shin, J., Yang, J., Kim, H., Jung, Y., Oh, H., Kim, Y., Hwang, J., Park, M., Ban, C., Jeong, K. J., Kim, S.-K., & Kweon, D.-H. (2020). Plasmid Display for Stabilization of Enzymes Inside the Cell to Improve Whole-Cell Biotransformation Efficiency. <em>Frontiers in Bioengineering and Biotechnology, 7</em>. <a href="https://doi.org/10.3389/fbioe.2019.00444" target="_blank">https://doi.org/10.3389/fbioe.2019.00444</a></p> | |
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Revision as of 08:37, 30 September 2024
Half-Staple: Oct1-DBD
Oct1-DBD is the DNA-binding domain of the human Oct1 transcription factor, it can be readily fused with other DNA-bindig proteins to form a functional staple for DNA-DNA proximity. We used this part as a component for our Simple staple (BBa_K5237006) resulting in a bivalent DNA binding staple, and also fused to mNeonGreen, as part of a FRET readout system (BBa_K5237016).
Contents
The 3D organization of the genome plays a crucial role in regulating gene expression in eukaryotic cells,
impacting cellular behavior, evolution, and disease. Beyond the linear DNA sequence, the spatial arrangement of
chromatin, influenced by DNA-DNA interactions, shapes pathways of gene regulation. However, the tools to precisely
manipulate this genomic architecture remain limited, rendering it challenging to explore the full potential of the
3D genome in synthetic biology. We - iGEM Team Heidelberg 2024 - have developed PICasSO, a powerful molecular
toolbox based on various DNA-binding proteins to address this issue.
The PICasSO part collection offers a comprehensive, modular platform for precise manipulation and re-programming of DNA-DNA interactions using protein staples in living cells, enabling researchers to recreate natural 3D genomic interactions, such as enhancer hijacking, or to design entirely new spatial architectures for gene regulation. Beyond its versatility, PICasSO includes robust assay systems to support the engineering, optimization, and testing of new staples, ensuring functionality in vitro and in vivo. We took special care to include parts crucial for testing every step of the cycle (design, build, test, learn) when engineering new parts
At its heart, the PICasSO part collection consists of three categories.
(i) Our DNA-binding proteins
include our
finalized enhancer hijacking Cas staple as well as half staples that can be used by scientists to compose entirely
new Cas staples in the future. We also include our simple staples that serve as controls for successful stapling
and can be further engineered to create alternative, simpler and more compact staples.
(ii) As functional elements, we list additional parts that enhance the functionality of our Cas and Basic staples. These
consist of
protease-cleavable peptide linkers and inteins that allow condition-specific, dynamic stapling in vivo.
Besides staple functionality, we also include the parts to enable the efficient delivery of PICasSO's constructs with our
interkingdom conjugation system.
(iii) As the final component of our collection, we provide parts that support the use of our custom readout
systems. These include components of our established FRET-based proximity assay system, enabling users to
confirm
accurate stapling. Additionally, we offer a complementary, application-oriented testing system for functional
readout via a luciferase reporter, which allows for straightforward experimental simulation of enhancer hijacking.
The following table gives a complete overview of all parts in our PICasSO toolbox. The highlighted parts showed
exceptional performance as described on our iGEM wiki and can serve as a reference. The other parts in the
collection are versatile building blocks designed to provide future iGEMers with the flexibility to engineer their
own custom Cas staples, enabling further optimization and innovation.
Our part collection includes:
DNA-binding proteins: The building blocks for engineering of custom staples for DNA-DNA interactions with a modular system ensuring easy assembly. | ||
BBa_K5237000 | fgRNA Entryvector MbCas12a-SpCas9 | Entryvector for simple fgRNA cloning via SapI |
BBa_K5237001 | Staple subunit: dMbCas12a-Nucleoplasmin NLS | Staple subunit that can be combined to form a functional staple, for example with fgRNA and dCas9 |
BBa_K5237002 | Staple subunit: SV40 NLS-dSpCas9-SV40 NLS | Staple subunit that can be combined to form a functional staple, for example with our fgRNA or dCas12a |
BBa_K5237003 | Cas-Staple: SV40 NLS-dMbCas12a-dSpCas9-Nucleoplasmin NLS | Functional Cas staple that can be combined with sgRNA or fgRNA to bring two DNA strands in close proximity |
BBa_K5237004 | Staple subunit: Oct1-DBD | Staple subunit that can be combined to form a functional staple, for example with TetR. Can also be combined with a fluorescent protein as part of the FRET proximity assay |
BBa_K5237005 | Staple subunit: TetR | Staple subunit that can be combined to form a functional staple, for example with Oct1. Can also be combined with a fluorescent protein as part of the FRET proximity assay |
BBa_K5237006 | Simple taple: TetR-Oct1 | Functional staple that can be used to bring two DNA strands in close proximity |
BBa_K5237007 | Staple subunit: GCN4 | Staple subunit that can be combined to form a functional staple, for example with rGCN4 |
BBa_K5237008 | Staple subunit: rGCN4 | Staple subunit that can be combined to form a functional staple, for example with rGCN4 |
BBa_K5237009 | Mini staple: bGCN4 | Assembled staple with minimal size that can be further engineered | Functional elements: Protease cleavable peptide linkers and inteins are used to control and modify staples for further optimization for custom applications. |
BBa_K5237010 | Cathepsin B-Cleavable Linker (GFLG) | Cathepsin B cleavable peptide linker, that can be used to combine two staple subunits ,to make responsive staples |
BBa_K5237011 | Cathepsin B Expression Cassette | Cathepsin B which can be selectively express to cut the cleavable linker |
BBa_K5237012 | Caged NpuN Intein | Undergoes protein transsplicing after protease activation, can be used to create functionalized staple units |
BBa_K5237013 | Caged NpuC Intein | Undergoes protein transsplicing after protease activation, can be used to create functionalized staple units |
BBa_K5237014 | fgRNA processing casette | Processing casette to produce multiple fgRNAs from one transcript, can be used for multiplexing |
BBa_K5237015 | Intimin anti-EGFR Nanobody | Interkindom conjugation between bacteria and mammalian cells, as alternative delivery tool for large constructs | Readout Systems: FRET and enhancer recruitment to measure proximity of stapled DNA in bacterial and mammalian living cells enabling swift testing and easy development for new systems. |
BBa_K5237016 | FRET-Donor: mNeonGreen-Oct1 | Donor part for the FRET assay binding the Oct1 binding cassette. Can be used to visualize DNA-DNA proximity |
BBa_K5237017 | FRET-Acceptor: TetR-mScarlet-I | Acceptor part for the FRET assay binding the TetR binding cassette. Can be used to visualize DNA-DNA proximity |
BBa_K5237018 | Oct1 Binding Casette | DNA sequence containing 12 Oct1 binding motifs, can be used for different assays such as the FRET proximity assay |
BBa_K5237019 | TetR Binding Cassette | DNA sequence containing 12 Oct1 binding motifs, can be used for different assays such as the FRET proximity assay | BBa_K5237020 | Cathepsin B-Cleavable Trans-Activator: NLS-Gal4-GFLG-VP64 | Readout system that responds to protease activity. It was used to test Cathepsin-B cleavable linker. |
BBa_K5237021 | NLS-Gal4-VP64 | Trans-activating enhancer, that can be used to simulate enhancer hijacking. | BBa_K5237022 | mCherry Expression Cassette: UAS, minimal Promotor, mCherry | Readout system for enhancer binding. It was used to test Cathepsin-B cleavable linker. |
BBa_K5237023 | Oct1 - 5x UAS binding casette | Oct1 and UAS binding cassette, that was used for the simulated enhancer hijacking assay. |
BBa_K5237024 | TRE-minimal promoter- firefly luciferase | Contains Firefly luciferase controlled by a minimal promoter. It was used as a luminescence readout for simulated enhancer hijacking. |
1. Sequence overview
Sequence and Features
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2. Usage and Biology
Oct1-DBD is the DNA-binding domain of the human transcription factor Oct1 (POU2F1), which plays a key role in gene regulation, immune response, and stress adaptation in eukaryotic cells. This domain specifically binds to the octamer motif (5'-ATGCAAAT-3') within promoter and enhancer regions, influencing transcriptional activity (Lundbäck et al., 2000). The Oct1-DBD consists of both a POU-specific domain and a POU homeodomain, which work together to form a stable complex with DNA (Park et al., 2013, Stepchenko et al. 2021).
In synthetic biology, Oct1-DBD was previously used for plasmid display technology due to its strong binding affinity (KD = 9 × 10-11 M). Proteins fused with Oct1-DBD showed increased expression and protein solubility (Parker et al. 2020).
This part was further used in BBa_K5237002 as a fusion with tetR, resulting in a bivalent DNA binding staple, and also fused to mNeonGree, as part of a FRET readout system (BBa_K5237016).
3. Assembly and part evolution
The Oct1-DBD amino acid sequence was obtained from UniProt (P14859, POU domain, class 2, transcription factor 1) and DNA binding domain extracted based on information given from Park et al. 2013 & 2020. An E. coli codon optimized DNA sequence was obtained through gene synthesis and used to clone further constructs
4. Results
Oct1 was N-terminally fused to the His6-mNeonGreen. The fusion protein was expressed from a T7 based expression plasmid and subsequently purified using metal affinity chromatography with Ni-NTA beads.(Figure 2, left) DNA binding affinity was estimated with an electrophoretic mobility shift assay (EMSA). For this, three different buffer conditions were tested (Binding buffer 1: 137 mM NaCl, 2.7 mM KCl, 10 mM Na2HPO4, 1.8 mM KH2HPO4, 0.1 % (v/v) IGEPAL® CA-360, 1 mM EDTA; Binding buffer 2: 10 mM Tris, 50 mM KCl; NaP250: Na2HPO4, 150 mM NaCl, 250 mM Imidazol). DNA binding could only be detected for Binding buffer 1. (Figure 2, right)
5. References
Lundbäck, T., Chang, J.-F., Phillips, K., Luisi, B., & Ladbury, J. E. (2000). Characterization of Sequence-Specific DNA Binding by the Transcription Factor Oct-1. Biochemistry, 39(25), 7570–7579. https://doi.org/10.1021/bi000377h
Park, J. H., Kwon, H. W., & Jeong, K. J. (2013). Development of a plasmid display system with an Oct-1 DNA-binding domain suitable for in vitro screening of engineered proteins. Journal of Bioscience and Bioengineering, 116(2), 246–252. https://doi.org/10.1016/j.jbiosc.2013.02.005
Park, Y., Shin, J., Yang, J., Kim, H., Jung, Y., Oh, H., Kim, Y., Hwang, J., Park, M., Ban, C., Jeong, K. J., Kim, S.-K., & Kweon, D.-H. (2020). Plasmid Display for Stabilization of Enzymes Inside the Cell to Improve Whole-Cell Biotransformation Efficiency. Frontiers in Bioengineering and Biotechnology, 7. https://doi.org/10.3389/fbioe.2019.00444
Stepchenko, A. G., Portseva, T. N., Glukhov, I. A., Kotnova, A. P., Lyanova, B. M., Georgieva, S. G., & Pankratova, E. V. (2021). Primate-specific stress-induced transcription factor POU2F1Z protects human neuronal cells from stress. Scientific Reports, 11(1), 18808. https://doi.org/10.1038/s41598-021-98323-y