Team:Penn/AssayValidation

From 2013.igem.org

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<h4><b>Standardized Bisulfite Sequencing Primers.</b></h4> Bisulfite sequencing is a good next step to further characterize functional site-specific methylases but it is inherently very difficult to design good primers. People will use advanced algorithms for primer design, and are still not guaranteed to be successful for some sequences. We went through 8 sets of primers, most of which did not show the proper bias to amplify only bisulfite converted DNA. Primer Set 2 was successful and is included with our MaGellin plasmid, much like VF and VR are included as standardized biobrick sequencing primers (Figure 3).
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<h4><b>We have designed standardized bisulfite sequencing primers.</b></h4> Bisulfite sequencing is a good next step after restriction digest to further characterize functional site-specific methylases, but it is inherently very difficult to design good primers. People use advanced algorithms for primer design that are still not guaranteed to successfully sequence some sequences. We went through 8 sets of primers, most of which did not show the proper bias to amplify only bisulfite converted DNA. Primer Set 2 was successful and is included with our MaGellin plasmid, much like VF and VR are included as standardized biobrick sequencing primers (Figure 3).
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<div style="margin-left:auto;margin-right:auto;text-align:center"><figure><img border="0" src="https://static.igem.org/mediawiki/2013/thumb/4/4a/Biseq.png/631px-Biseq.png" alt="Workflow" width="400" ><figcaption><i>Figure 3: Validating standardized bisulfite sequencing primers. Primer Set 2 successfully amplify converted DNA but not unconverted DNA, as desired.</i></figcaption></figure></div>
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<div style="margin-left:auto;margin-right:auto;text-align:center"><figure><img border="0" src="https://static.igem.org/mediawiki/2013/thumb/4/4a/Biseq.png/631px-Biseq.png" alt="Workflow" width="400" ><figcaption><i>Figure 3: Validating standardized bisulfite sequencing primers. Primer Set 2 successfully amplifies bisulfite converted DNA but not unconverted DNA, as desired.</i></figcaption></figure></div>
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<h4><b>In Vitro.</b></h4> First, we tested MaGellin with a purified methyltransferase in vitro. The results made it clear that MaGellin can detect methylation, at both the “target” and “off-target” site (Figure 4). MaGellin is also sensitive to various degrees of methylation (Figure 5). These experiments helped us optimize the ideal amount of plasmid and restriction enzyme to use in any study moving forward.
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<h4><b>MaGellin effectively detects methylation in vitro.</b></h4> First, we tested MaGellin with a purified methylase in vitro. The results made it clear that MaGellin can detect methylation at both the “target” and “off-target” site (Figure 4). MaGellin is also sensitive to various degrees of methylation (Figure 5). These experiments helped us optimize the ideal amount of plasmid and restriction enzyme to use in any study moving forward.
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<div style="margin-left:auto;margin-right:auto;text-align:center"><figure><img border="0" src="https://static.igem.org/mediawiki/2013/5/58/Methylation_timecourse.png" alt="Timecourse" height="395"><figcaption><i>Figure 5: Plasmid DNA treated in vitro with purified M.SssI. Each lane was treated for a different amount of time, this figure shows MaGellin's sensitivity.</i></figcaption></figure></div>
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<div style="margin-left:auto;margin-right:auto;text-align:center"><figure><img border="0" src="https://static.igem.org/mediawiki/2013/5/58/Methylation_timecourse.png" alt="Timecourse" height="395"><figcaption><i>Figure 5: Plasmid DNA treated in vitro with purified M.SssI. Each lane was treated for a different amount of time, this figure shows that MaGellin is sensitive to varying levels of methylation.</i></figcaption></figure></div>
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<h4><b>In vivo.</b> </h4> Then, we expressed M.SssI in vivo and compared it with purified M.SssI used on the plasmid in vitro. In both cases, we saw similar full methylation of the plasmid, confirming that MaGellin can express methylases and report their activity in vivo (Figure 6).
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<h4><b>MaGellin detects methylation in vivo.</b> </h4> We expressed M.SssI in vivo and compared it with purified M.SssI used on the plasmid in vitro. In both cases, we saw similar full methylation of the plasmid, confirming that MaGellin can express methylases and report their activity in vivo (Figure 6).
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<center><h1>Summary</center>
<center><h1>Summary</center>
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We have created MaGellin, a new technology that facilitates screening novel DNA binding domain – methyltransferase fusion proteins
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We have created MaGellin, a new technology that facilitates screening novel DNA binding domain – methylase fusion proteins
<li>Our assay is less expensive and faster than existing methods</li>
<li>Our assay is less expensive and faster than existing methods</li>
<li>We have eliminated noise associated with previous studies</li>
<li>We have eliminated noise associated with previous studies</li>

Revision as of 01:33, 29 October 2013

Penn iGEM

Assay Validation




For a detailed, graphical explanation of the MaGellin work flow, please download the MaGellin Workflow Specifications Sheet, which includes all of the steps in the MaGellin workflow.

We have designed standardized bisulfite sequencing primers.

Bisulfite sequencing is a good next step after restriction digest to further characterize functional site-specific methylases, but it is inherently very difficult to design good primers. People use advanced algorithms for primer design that are still not guaranteed to successfully sequence some sequences. We went through 8 sets of primers, most of which did not show the proper bias to amplify only bisulfite converted DNA. Primer Set 2 was successful and is included with our MaGellin plasmid, much like VF and VR are included as standardized biobrick sequencing primers (Figure 3).



Workflow
Figure 3: Validating standardized bisulfite sequencing primers. Primer Set 2 successfully amplifies bisulfite converted DNA but not unconverted DNA, as desired.


MaGellin effectively detects methylation in vitro.

First, we tested MaGellin with a purified methylase in vitro. The results made it clear that MaGellin can detect methylation at both the “target” and “off-target” site (Figure 4). MaGellin is also sensitive to various degrees of methylation (Figure 5). These experiments helped us optimize the ideal amount of plasmid and restriction enzyme to use in any study moving forward.


InVitro
Figure 4: Plasmid DNA treated in vitro with purified M.SssI. The first three lanes were not treated and show zero methylation detection by our assay. The last three lanes were methylated and show 100% methylation. This figure validates that MaGellin is capable of clear input/output.



Timecourse
Figure 5: Plasmid DNA treated in vitro with purified M.SssI. Each lane was treated for a different amount of time, this figure shows that MaGellin is sensitive to varying levels of methylation.



MaGellin detects methylation in vivo.

We expressed M.SssI in vivo and compared it with purified M.SssI used on the plasmid in vitro. In both cases, we saw similar full methylation of the plasmid, confirming that MaGellin can express methylases and report their activity in vivo (Figure 6).


InVivo
Figure 6: M.SssI expressed in vivo compared with in vitro methylation.



Summary

    We have created MaGellin, a new technology that facilitates screening novel DNA binding domain – methylase fusion proteins
  1. Our assay is less expensive and faster than existing methods
  2. We have eliminated noise associated with previous studies
  3. We have a system with clear input/output
  4. Our assay lends itself to high throughput screening of many different proteins
  5. We are releasing it alongside an open source data analysis software package which streamlines the entire screening process


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