Characterization of a Deinococcus radiodurans MazF: A UACA-specific RNA endoribonuclease.

Microbes are known to withstand environmental stresses by using chromosomal toxin-antitoxin systems. MazEF is one of the most extensively studied toxin-antitoxin systems. In stressful environments, MazF toxins modulate translation by cleaving single-stranded RNAs in a sequence-specific fashion. Previously, a chromosomal gene located at DR0417 in Deinococcus radiodurans was predicted to code for a MazF endoribonuclease (MazF(DR0417)); however, its function remains unclear. In the present study, we characterized the molecular function of MazF(DR0417). Analysis of MazF(DR0417)-cleaved RNA sites using modified massively parallel sequencing revealed a unique 4-nt motif, UACA, as a potential cleavage pattern. The activity of MazF(DR0417) was also assessed in a real-time fluorometric assay, which revealed that MazF(DR0417) strictly recognizes the unique tetrad UACA. This sequence specificity may allow D. radiodurans to alter its translation profile and survive under stressful conditions.