Wet Lab Collaboration with the iGEM Team TU Darmstadt 2016
The iGEM team of TU Darmstadt developed a biosafety system that makes bacteria strains survive only at laboratory conditions. The idea is that they require a specific unnatural amino acid in the medium. In case the cells leave this environment, the bacterial genome is degraded by the DNase Colicin E2, leading to cell death and destruction of the genetic information. This system might impede accidental or deliberate release of GMOs and therefore tackles the problems of corporate espionage and ecological consequences of GMOs.
The DNase Colicin E2 consists of 3 domains: a cell export domain, a cell import domain and a DNase domain. The team of TU Darmstadt developed a minimalized version of this protein, containing only the DNase domain. This protein (mColWT), as well as a mutated version (mColmut; C266A), was put behind a T7 Promoter on the plasmid pSB1A3. After transformation of both constructs into E. coli TOP10 and BL21, Team Darmstadt observed a significantly lower colony count for mColWT than for mColmut on LB Agar supplemented with Ampicillin. In order to check if this apparent toxic effect of mColWT is also oberservable in other strains, we tested mColWT and mColmut via transformation in Shimwellia blattae (a strain we are using in our project) at our lab in Göttingen. Empty pSB1A3 was also transformed into S. blattae, in order to check if the plasmid is compatible with the strain.
All transformations were successful, but no significant difference in the colony count between mColWT (960 and 776 colonies; upper plates in figure 1) and mColmut (628 and 984 colonies; lower plates in figure 1) could be observed (Fig. 1).