Team:INSA-Lyon/Project/Stage1/Strategy

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<img src="http://lh3.ggpht.com/_Uc3bmii-yi0/TMgfmJf-2aI/AAAAAAAAAmY/MmQgbaghPRs/sequenceStrategieStage1.PNG" alt="Sequence" title="Sequence" >
<img src="http://lh3.ggpht.com/_Uc3bmii-yi0/TMgfmJf-2aI/AAAAAAAAAmY/MmQgbaghPRs/sequenceStrategieStage1.PNG" alt="Sequence" title="Sequence" >
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<p>(The A from the ATG of the coding sequence completes the Xba1 site)</p>
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<p>We also got the three genes directly from the iGEM registry, and we tried to ligate
<p>We also got the three genes directly from the iGEM registry, and we tried to ligate
them. The BioBricks we used are : <a href="http://partsregistry.org/wiki/index.php?title=Part:BBa_K156012">BBa_K156012</a> for phaA, <a href="http://partsregistry.org/wiki/index.php?title=Part:BBa_K156013">BBa_K156013</a> for phaB and <a href="http://partsregistry.org/wiki/index.php?title=Part:BBa_K156014">BBa_K156014</a> for phaC.</p>
them. The BioBricks we used are : <a href="http://partsregistry.org/wiki/index.php?title=Part:BBa_K156012">BBa_K156012</a> for phaA, <a href="http://partsregistry.org/wiki/index.php?title=Part:BBa_K156013">BBa_K156013</a> for phaB and <a href="http://partsregistry.org/wiki/index.php?title=Part:BBa_K156014">BBa_K156014</a> for phaC.</p>
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<p>Unfortunately, we never managed to cut the phaC gene we found by the Xba1 enzyme so we couldn’t use our new
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operon.</p>
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<p>Our two final strategies were to ligate phaC with either PCR product either iGEM <span style="font-style:italic>phaA</span> and <span style="font-style:italic>phaB</span>.
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With more time we could have designed a primer with the right restriction sites but we were not
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sure the <span style="font-style:italic>phaC</span> gene had just this problem.</p>
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Revision as of 15:15, 27 October 2010





Strategy



Complete plasmid synthesis : pILI1



In 1988, Slater et al. (Journal of Bacteriology) developed the plasmid pSB20. Then the construction of a total DNA bank of Alcaligenes eutrophus permits to identified two restriction sites which surround the three genes and their promoter: KpnI and EcoRI. With the help of a software (Serial Cloner) and the sequence of Ralstonia eutropha (old named Alcaligenes eutrophus), a 5800 pb length sequence had been isolated. It contains the promoter and the phaCAB genes. This sequence had been inserted into a plasmid pUC18. A HindIII site had been added before the promoter and also a unique restriction site XhoI between the promoter and the operon (so we could change the promoter). This is our plasmid pILI1.

Plasmid pILI1 map (Adapted from PlasMapper and BPROM online softwares)

Plasmid pILI1 map (Adapted from PlasMapper and BPROM online softwares)



We send this sequence to GeneCust to be synthesized. The product of this synthesis had been transformed in competent bacteria NM522.

However this plasmid doesn’t match with the iGEM criteria. Indeed some forbidden restriction sites were present in the sequence.




PhaCAB Operon: two strategies to construct a standard BioBrick



Design and PCR


We designed a Sequence

(The A from the ATG of the coding sequence completes the Xba1 site)




In parallel, we performed a PCR to get phaB from the pILI1 sequence because no iGEM restriction sites were on the sequence and the sequences of those genes were short enough. We designed them using a software to make them the most stable and the most specific that we could, adding the prefix sequence at the beginning of the forward primer and the suffix sequence at the end of the reverse primer. Then we wanted to ligate the three genes in the original order.

Strategy with PCR

First strategy for ligation



Using iGEM Regestry


We also got the three genes directly from the iGEM registry, and we tried to ligate them. The BioBricks we used are : BBa_K156012 for phaA, BBa_K156013 for phaB and BBa_K156014 for phaC.



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