Difference between revisions of "Team:Jilin China/Description"
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Latest revision as of 17:30, 19 October 2016
Improvement
We were inspired by the pioneer work from the TecMonterrey team of 2013 iGEM competition, which demonstrated that the TAT-Apoptin could kill tumor cells. Furthermore, they used a hypoxia promoter from E. coli to regulate the expression of TAT-Apoptin so that this protein could be expressed in the anaerobic regions, such as regions inside the solid tumors.
Although TAT-Apoptin could induce the apoptosis of tumor cells effectively, it seemed that E. coli was not a suitable vehicle to deliver TAT-Apoptin into tumors. We thought that anaerobic microorganisms might be more effective than E. coli to target the tumor tissues. After extensive literature searching and consulting with experts from different research fields, we found that Bifidobacterium longum (B.longum) should be an ideal vehicle to deliver TAT-Apoptin. First, B. longum only grows in anaerobic regions, which means that the expression of TAT-Apoptin from B. longum can only happen in anaerobic regions, such as the anaerobic regions inside solid tumors. More importantly, B. longum is safe to human body since it produces no toxin to the host. Furthermore, it has anti-tumor biological effects. Considering all these information, we have chosen B. longum instead of E.coli to express the TAT-Apoptin.
Improvement
To facilitate the expression of TAT-apoptin in B. longum, many biobricks have been replaced or added in the devices. First of all, Tmp1, originally cloned from the plasmid of Bifidobacterium that contains one ori and two orf sequences was added as the first biobrick to regulate the expression of the TAT-apoptin in B. longum. In addition, the promoter and RBS sequence from hup gene of B.longum that could function in the recombinant plasmid inside B. longum was also added to regulate the expression of this protein. To facilitate the secretion of TAT-apoptin, the signal peptides of Sec2 and Tmp1 were added to direct the secretion process of the fused protein in two separate devices. To confirm the function of TAT-Apoptin and extend the work of the TecMonterrey team, the two devices were transformed into B.longum and the animal experiments were done, which showed that our idea is feasible. More details about the experiments are available in our wiki.
