Ljubljana

From 2007.igem.org

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<title>Company Name</title>
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     <div id="about">       
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     <div align="justify" id="about">       
       <p class="p1"><span><b>Synthetic biology provides the possibility to extend our defense against disease by employing our intelligence. In the spirit of synthetic biology we can combine different functional parts with known properties to assemble new cellular functions which do not yet exist in nature.</b></span></p>
       <p class="p1"><span><b>Synthetic biology provides the possibility to extend our defense against disease by employing our intelligence. In the spirit of synthetic biology we can combine different functional parts with known properties to assemble new cellular functions which do not yet exist in nature.</b></span></p>
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<h3><span>Abstract for nonspecialists</span></h3>
<h3><span>Abstract for nonspecialists</span></h3>
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<div align="justify">
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HIV-1 virus is one of the most difficult targets for therapy because it hijacks the cells of our immune system and particularly because the virus mutates rapidly making it drug resistant. Current therapy uses combinations of different drugs, since it is less probable for the virus to develop the resistance against all of them simultaneously.
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The main problem of effective treatment of HIV infection is rapid mutation rate which makes the virus resistant against drugs. Current therapy uses combinations of different drugs, since it is less probable for the virus to develop the resistance against all of them simultaneously. Our approach was to construct a defense system based on the principles of synthetic biology, which is based on viral function to activate the defense response in the attacked cell. The effect of mutations can thus be avoided since those mutations that cause the loss of the function also render the virus harmless. We successfully implemented two types of defense devices – one based on the viral attachment to the cell and another based on the viral maturation. Activation of any of them activates the antiviral cell defense or alternatively kills the infected cells, preventing further spread of infection. The same approach could be implemented for defense against other viral infections.
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We propose a different strategy, where we target a specific <b>FUNCTION</b> of virus, rather than any particular sequence. This viral function triggers a cellular response which can either employ antiviral defense or lead to a destruction of infected cells to prevent spread of the infection.
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The effect of mutations can thus be avoided since those mutations that cause the loss of the function also render the virus harmless. We successfully implemented two types of defense devices – one based on the viral attachment to the cell and another based on the viral maturation. In our system activation of any of them activates the antiviral cell defense or alternatively kills the infected cells, preventing further spread of infection. The same approach could be implemented for defense against other viral infections.
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</div>
<br><br>
<br><br>
   
   
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<h3><span>Scientific abstract</span></h3>
 
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We have devised a synthetic system of antiviral defense against the HIV-1 infection that is not sensitive to viral mutations, because it is based on viral functions. Two essential viral functions have been successfully implemented to activate the cellular defense – viral attachment to cells through a pair of surface receptors and processing of viral proteins by its own protease.
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          <object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000" codebase="http://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=8,0,0,0" width="600" height="500" id="team2" > <param name="allowScriptAccess" value="sameDomain" /> <param name="movie" value="https://static.igem.org/mediawiki/2007/8/86/Split_ubiquitin.swf" /><param name="quality" value="high" /><param name="bgcolor" value="#ffffff" /><embed src="https://static.igem.org/mediawiki/2007/8/86/Split_ubiquitin.swf" quality="high" bgcolor="#ffffff" width="600" height="500" name="team2" allowScriptAccess="sameDomain" type="application/x-shockwave-flash" pluginspage="http://www.macromedia.com/go/getflashplayer" />
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Animation of split-ubiquitin system.
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Binding of virus to human cells causes formation of CD4-CCR5 heterodimers, which reconstitutes the split TEV protease. This protease cleaves-off the membrane-anchored T7 RNA polymerase from the membrane, directing it into the nucleus. T7 RNA polymerase provides the amplification of the signal and causes transcription of versatile effector genes, coding either for antiviral proteins or for caspase, which leads the infected cell into apoptosis thereby preventing further spread of viral infection. The same type function was successfully utilized in the implementation of the split ubiquitin system.
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<br><br>
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<h3><span>Scientific abstract</span></h3>
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<div align="justify">
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We have devised a synthetic system of antiviral defense against the HIV-1 infection that is not sensitive to viral mutations, because it is based on viral functions. <b>Two essential viral functions</b> have been successfully implemented to activate the cellular defense – viral attachment to cells through a pair of surface receptors and processing of viral proteins by its own protease.
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Our second approach was to exploit the viral protease, which cleaves the specific linker introduced between the T7 RNA polymerase and a cellular membrane anchor. Released T7 RNA polymerase subsequently activates the defense similar to that described with the split protein system. All three systems have been shown to work in human cells.
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Binding of virus to human T-cells causes formation of CD4-CCR5 heterodimers, which in our system reconstitutes the split ubiquitin. This protease cleaves-off the membrane-anchored T7 RNA polymerase from the membrane, directing it into the nucleus. T7 RNA polymerase provides the amplification of the signal and causes transcription of <b>versatile effector genes</b>, coding either for antiviral proteins or for caspase, which leads the infected cell into apoptosis thereby preventing further spread of viral infection. The same viral function was successfully utilized in the implementation of the split TEV protease system.
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The second implementation of this idea was to utilize the activity of HIV-protease, which is required for viral maturation and cleaves a specific amino acid sequence. This target sequence was engineered between the membrane anchor and T7 RNA polymerase. T7 RNA polymerase released from the membrane subsequently activates the defense similar to that described with the split protein system. <b>All three systems work in human cells.</b> We have prepared and tested many different constructs, contributing more than 70 new BioBricks and successfully demonstrated activation of response gene by infection of mammalian cell cultures with HIV-1 pseudovirus.
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      <h3><span>Executive summary</span></h3>
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      <p class="p1"><span>HIV-1 virus is one of the most difficult targets for therapy because it hijacks our immune system and particularly because the virus mutates rapidly. This allows the  selection of mutated variant strains which bypass the inhibitors that bind to specific residues on their targets. Currently the most effective therapy consists of an inhibitor cocktail that decreases the probability of HIV to overcome all target sequences at the same time.<br><br>
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We propose a different strategy, where we target a specific <b>FUNCTION</b> of virus, rather than any particular sequence. This viral function triggers a cellular response which can either employ antiviral defense or lead to a destruction of infected cells to prevent spread of the infection.<br><br>
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For implementation of this idea we have selected <b><u>two viral functions:</u></b> <b>viral attachment</b> to the cellular co-receptors CD4 and CCR5 and <b>viral proprotein processing</b> by its own protease.
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Binding of virus to T-cells leads to the formation of CD4-CCR5 heterodimer. In our device, formation of this heterodimer triggers reconstitution of a split protein (split ubiquitin or TEVP) which activates the specific proteolytic activity. This releases the T7 RNA polymerase from the membrane anchor and leads to transcription of the effector gene, which prevents the spread of viral infection.<br>
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The second implementation of this idea was to utilize the HIV-protease, which is required for viral maturation and cleaves a specific amino acid sequence. This target sequence was engineered between the membrane anchor and T7 polymerase. Activation of viral protease similarly as above releases the T7 polymerase and starts the defense program.<br><br>
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Important points of both approaches are to use the amplification of the signal, achieved by the use of T7 polymerase and the system's versatility, as we can select any number of different genes to be activated by the detection of viral function. The crucial aspect of our approach is that this system is <b>not sensitive to viral mutations</b> and is not activated only in case where the mutation leads to the loss of the viral function, which however also renders virus harmless at the same time.<br><br>
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We have prepared and tested many different constructs, contributing more than 70 new BioBricks and successfully demonstrated activation of response gene by infection of mammalian cell cultures with HIV-1 pseudovirus.<br><br>
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   <p class="MsoNormal"><o:p><b>PLEDGE:</b> All experimental work on this project was performed from May to October 2007 by the undergraduate students participating in the team under the tutorial of instructors. All the students participated at iGEM for the first time.</o:p></p>
   <p class="MsoNormal"><o:p><b>PLEDGE:</b> All experimental work on this project was performed from May to October 2007 by the undergraduate students participating in the team under the tutorial of instructors. All the students participated at iGEM for the first time.</o:p></p>
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   <td><a href="http://www.ki.si/"> National Institute of Chemistry</a> <br>
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   <td><a href="http://www.ki.si/">National Institute of Chemistry</a> <br>
   <a href="http://www.ki.si/"><img border="0" src="https://static.igem.org/mediawiki/2007/2/29/KIlogo.gif" width="110" height="70"><br></a><br></td>
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   <td><a href="http://www.uni-lj.si/en/">University of Ljubljana </a> <br>
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   <td><br><a href="http://www.uni-lj.si/en">University of Ljubljana</a> <br>
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   <a href="http://www.uni-lj.si/en/"><img border="0" src="https://static.igem.org/mediawiki/2007/e/ea/Menuleft_logo_unilj.gif" width="52" height="104"> <br></a> <br></td>
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   <a href="http://www.uni-lj.si/en/"><img border="0" src="https://static.igem.org/mediawiki/2007/3/33/UL-logo.jpg"> <br></a></td>
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<div id="ldiscussion">
<div id="ldiscussion">
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<ul><li><a class="one" href="https://2007.igem.org/Ljubljana/glossary">Terms & References</a>&nbsp; </li>
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<ul><li><a class="one" href="https://2007.igem.org/Ljubljana/glossary">Glossary & References</a>&nbsp; </li>
<li><a class="one" href="https://2007.igem.org/Ljubljana/acknowledgements">Acknowledgements</a>&nbsp; </li>
<li><a class="one" href="https://2007.igem.org/Ljubljana/acknowledgements">Acknowledgements</a>&nbsp; </li>
         </ul>
         </ul>

Latest revision as of 18:36, 23 November 2007

Company Name



Synthetic biology provides the possibility to extend our defense against disease by employing our intelligence. In the spirit of synthetic biology we can combine different functional parts with known properties to assemble new cellular functions which do not yet exist in nature.

Abstract for nonspecialists

HIV-1 virus is one of the most difficult targets for therapy because it hijacks the cells of our immune system and particularly because the virus mutates rapidly making it drug resistant. Current therapy uses combinations of different drugs, since it is less probable for the virus to develop the resistance against all of them simultaneously. We propose a different strategy, where we target a specific FUNCTION of virus, rather than any particular sequence. This viral function triggers a cellular response which can either employ antiviral defense or lead to a destruction of infected cells to prevent spread of the infection. The effect of mutations can thus be avoided since those mutations that cause the loss of the function also render the virus harmless. We successfully implemented two types of defense devices – one based on the viral attachment to the cell and another based on the viral maturation. In our system activation of any of them activates the antiviral cell defense or alternatively kills the infected cells, preventing further spread of infection. The same approach could be implemented for defense against other viral infections.



Animation of split-ubiquitin system.

Scientific abstract

We have devised a synthetic system of antiviral defense against the HIV-1 infection that is not sensitive to viral mutations, because it is based on viral functions. Two essential viral functions have been successfully implemented to activate the cellular defense – viral attachment to cells through a pair of surface receptors and processing of viral proteins by its own protease. Binding of virus to human T-cells causes formation of CD4-CCR5 heterodimers, which in our system reconstitutes the split ubiquitin. This protease cleaves-off the membrane-anchored T7 RNA polymerase from the membrane, directing it into the nucleus. T7 RNA polymerase provides the amplification of the signal and causes transcription of versatile effector genes, coding either for antiviral proteins or for caspase, which leads the infected cell into apoptosis thereby preventing further spread of viral infection. The same viral function was successfully utilized in the implementation of the split TEV protease system. The second implementation of this idea was to utilize the activity of HIV-protease, which is required for viral maturation and cleaves a specific amino acid sequence. This target sequence was engineered between the membrane anchor and T7 RNA polymerase. T7 RNA polymerase released from the membrane subsequently activates the defense similar to that described with the split protein system. All three systems work in human cells. We have prepared and tested many different constructs, contributing more than 70 new BioBricks and successfully demonstrated activation of response gene by infection of mammalian cell cultures with HIV-1 pseudovirus.


PLEDGE: All experimental work on this project was performed from May to October 2007 by the undergraduate students participating in the team under the tutorial of instructors. All the students participated at iGEM for the first time.

National Institute of Chemistry



University of Ljubljana