Cyanobacteria have evolved to survive stressful environmental changes by regulating growth, however, the underlying mechanism for this is obscure. The ability of chromosomal type II toxin-antitoxin (TA) systems to modulate growth or cell death has been documented in a variety of prokaryotes. A chromosomal locus of sp. PCC 7120 has been predicted as a putative TA system. Here we demonstrate that form a bicistronic operon that is co-transcribed under normal growth conditions. Overproduction of MazFa induced growth arrest which could be neutralized by co-expression of MazEa. MazFa also inhibited the growth of cells, and this effect could be overcome by simultaneous or subsequent expression of MazEa via formation of the MazEa-MazFa complex , further confirming the nature of the locus as a type II TA system. Interestingly, like most TA systems, deletion of had no effect on the growth of during the tested stresses. Our data suggest that , or together with other chromosomal type II TA systems, may promote cells to cope with particular stresses by inducing reversible growth arrest of .
Ning, D., Jiang, Y., Liu, Z., & Xu, Q. (2013). Characterization of a Chromosomal Type II Toxin-Antitoxin System mazEaFa in the Cyanobacterium Anabaena sp. PCC 7120. PLoS ONE, 8(2). https://doi.org/10.1371/journal.pone.0056035