The experiments of iGEM 2016 team Tokyo_Tech are divided into Toxin, AHL, AmiE, and temperature-dependent promoter assays. This section describes toxin assay. In our project, the mazEF system is studied, which is one of the most studied TA systems.

TA systems are found on the genomic DNA of many bacteria and they play important roles in controlling cell growth. Preceding iGEM teams have studied the following TA systems; ccdB - ccdA (iGEM 2014 team ULB-Brussels and iGEM 2013 team UGent), kid - kis, zeta - epsilon (iGEM 2014 team Wageningen UR) and hok - soc (iGEM 2015 team UMaryland) (Table. 3-1-0-1.). Almost all the iGEM teams dealing with TA systems aimed to use them as a kill switch or substitution for antibiotics.

Table 3-1-0-1 TA system that has been studied in the preceding iGEM.

On the other hand, we aimed to study cooperation of toxin and antitoxin in cells. Although UCSF 2012 showed the communication through TA systems including the mazEF system, they did not introduce toxin and antitoxin genes into a single cell and did not show the data on the whole mazEF system. Besides, some preceding teams failed to show enough data on TA systems. Our results show that cell growth can be controlled flexibly by manipulating expression ratio of mazE and mazF, implying new applicability of TA systems to many biotechnological fields and future iGEM projects.