The part is made up of the standard parts from partsregistry.
This gene sequence once expressed will produce colicin E7. This is an endonuclease with random cutting site and can kill various strains of EHEC bacteria. However, inside the host cell, immediatle after being produced, its toxicity is inhibited by Immunity protein (which is also expressed at the same time). These 2 proteins form a complex which is harmless to the host cell. Under SOS response, the host cell produces lysis protein, which cause the cell to lyze. At the same time, lysis protein remove Immunity protein from the complex with colE7. As a result, colE7 regains its toxicity and ability to kill the EHEC bacteria nearby. For information on lysis gene, please refer to our BBa_K117000 part.
Lysis gene (promotes lysis in colicin-producing bacteria strain)
This lysis gene encodes for the lysis protein in colicin-producing strains of bacteria. Once activated, it causes the host cell to lyze. It also removes the immunity protein out of colicin, and hence, activates the endonuclease activity of the colicin.
This part is the assembly of riboswitches followed by an important gene CheZ in keeping E.coli motile (BBa_K557001) finely tuned by small molecules and toggle switches (BBa_K228003) pushed on and off while memorizing current state. It would make it possible that bacterial colonies will automatically divide into two parts after certain time, during which riboswitches would act as the main power to drive two parts away from each other while toggle switches would play the role of giving birth to two 'different' kinds of bacteria in one colony.
Aptamer-CheZ: theophylline-sensitive synthetic riboswitch+phosphatase which dephosphorylates CheY-P
Escherichia coli, the strain has always been kept in the lab of USTC-IGEM
This part is composed of a theophylline-sensitive aptamer,which will pair the ribosome binding site of the downstream gene in the absence of theophylline and thus inhibit the translation of the gene while expose the ribosome binding site in the presence of theophylline, and the CheZ gene, which is a phosphatase which dephosphorylates CheY-P and causes the flagellum to rotate counterclockwise and is essential for keeping the motility of E.coli. Thus this part provides a ligand-inducible motility and makes it possible to guide E.coli by theophylline.
We found the sequence of this part in literature and tried to design primers to construct it. But we were faced with a challenging problem in primer design, which comes from the basic properties of the aptamer involved. The aptamer tends to pair the ribosome binding site in the absence of theophylline, which is true in PCR, and enables primers to pair to the corresponding parts and the new strand to elongate. We made contact with the author of our reference and found they took different strategies in assembling the aptamer to CheZ instead of PCR. But thanks to the warm help of Professor J. S. Parkinson and Professor J. P. Gallivan, we acquired the sequence of primers used in assembling the aptamer to another gene and designed our own after analyzing them: forward primer:5'-GTTTCGAATTCGCGGCCGCTTCTAGGGTGATACCAGCATCGTCTTGATGCCCTTGGCAGCACCCCGCTGCAAGACAACAAG ATGCAACCATCAATCAAACC-3' reverse primer:5'-GTTTCCTGCAGCGGCCGCTACTAGTATTATTAAAATCCAAGACTATCCAACAAATCGT-3' Besides, we used special protocal of PCR: 96℃ 10min 96℃ 30s, 56℃ 30s, 72℃ 1min for 16 cycles and each cycle the annealing temperature increases by 1℃ 96℃ 30s, 72℃ 30s, 72℃ 1min for 20 cycles 72℃ 10min
The part is made up of the standard parts from partsregistry, and some of the sub-parts are inverted by PCR.
It is a part which has two stable states--CI and CI434 and the orginal state can be either of the two. CI repressor is expressed after a CI434 repressible promoter, while the CI434 is expressed after a CI repressible promoter, thus the system can only stay in one state, when one is expressed and the other is repressed. The two states can be swicthed in certain conditions. In other words, the orginal state can be changed by exogenetic triggering. For example, the orginal state is CI, then you can use an gene which exogenetically expresses CI434 to trigger the bistable part into the state of CI434.
Conversion of the iGEM parts registry to SBOL2.1