DRP005030
Growth inhibition after MazF activation through specific alteration of cellular state rather than through near-indiscriminate RNA cleavage.
MazF is a toxin protein that cleaves RNAs at ACA sequences in Escherichia coli, and MazF activation causes growth inhibition (cell death and/or growth arrest). In order to investigate the cellular response following MazF activation, transcriptomic profile of mazF overexpressing cells was compared to that of control non-expressing cells. Out of 4,318 genes examined, 266 and 245 genes were found to be up- and down- regulated, respectively, albeit with the presence and the number of the ACA trimer in RNAs unrelated to RNA levels. Therefore, it is suggested that growth inhibition is not caused only by near-indiscriminate RNA cleavage. Pathways for thiamine, valine, leucine, and isoleucine metabolism were upregulated, whereas pathways for energy metabolism, ribosome biogenesis, and glycine, serine and threonine metabolism were downregulated. These results suggest that specific categories of genes are differentially expressed following MazF activation and that growth inhibition is the result of affirmative shift to the specific cellular state. In particular, cells shift to the limited energy acquisition state, which is one of the important reasons of growth inhibition. In addition, cryptic prophage, transposon-related, and other toxin genes were upregulated, implying activation of mobile genetic elements and crosstalk of the toxin-antitoxin systems.