Toxin-antitoxin (TA) systems are genetic elements that encode a relatively stable protein
toxin that inhibits cell growth and an unstable antitoxin that inhibits the deleterious effect
of the cognate toxin. Their biological function is not yet fully understood. However, they
are known to participate in many biological processes, most important being
postsegregational killing, abortive infection and bacterial persistence. They can be found
on plasmids as well as chromosomes of numerous archaea and bacteria, including
cyanobacterium Microcystis aeruginosa PPC 7806.
Despite the abundance of TA systems in the genome of this cyanobacterium, only a few
have been experimentally characterised so far. Therefore, our goal has been to express
two antitoxins and isolate the protein products from Escherichia coli cells.
Using bioinformatics tools, we collected and analysed the predicted TA pairs. From these,
we selected two and amplified their antitoxin sequences. Using molecular cloning
methods, we inserted the genes for the antitoxins Bh695_0426 and Bh695_0430 into the
cloning vector pJET1.2/blunt. However, transfer of the antitoxins into the expression
vector pET-28b(+) was unsuccessful.
Successful expression of antitoxin genes and the isolation of protein products would
enable further research of antitoxin function, structure and regulation of TA gene
expression. It would therefore be reasonable to repeat experiments with a few
adjustments.
|
