rRNA operon multiplicity as a bacterial genome stability insurance policy

Sebastien Fleurier, Tanja Dapa, Olivier Tenaillon, CiarĂ¡n Condon, Ivan Matic

Nucleic Acids Research, gkac332, https://doi.org/10.1093/nar/gkac332

The ability to modulate translation capacity, which resides greatly on a number of ribosomes, provides robustness in fluctuating environments. Because translation is energetically the most expensive process in cells, cells must constantly adapt the rate of ribosome production to resource availability. This is primarily achieved by regulating ribosomal RNA (rRNA) synthesis, to which ribosomal proteins synthesis is adjusted. The multiplicity of rRNA encoding operons per bacterial genome exceeds requirements for the maximal growth rates in non-stress conditions. In this study, the authors provide evidence that a major function of rRNA operon multiplicity is to ensure that individual operons are not saturated by RNA polymerases during adaptation to environmental fluctuations, which can result in catastrophic chromosome replication failure and cell death.

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