The rnc operon is negatively auto-regulated by transcript stability. rnc, the first gene in the operon codes for RNase III which cleaves the long rncO stem II leading to transcript degradation and a reduction in translation.
The rnc operon's self-limiting mechanism is implemented via transcript stability, with the RNC gene encoding RNase III that cleaves the lengthy rncO stem II, resulting in decreased translation and transcript breakdown.