A tightly controlled gene induction system that contributes to the study of lethal gene function in .

Effective control of gene expression is crucial for understanding gene function in both eukaryotic and prokaryotic cells. While several inducible gene expression systems have been reported in , a conditional pathogen that causes dental caries, the significant non-inducible basal expression in these systems seriously limits their utility, especially when studying lethal gene functions and molecular mechanisms. We introduce a tightly controlled xylose-inducible gene expression system, TC-Xyl, for . Western blot results and fluorescence microscopy analysis indicate that TC-Xyl exhibits an extremely low non-inducible basal expression level and a sufficiently high expression level post-induction. Further, by constructing a mutation in which the only source FtsZ is under the control of TC-Xyl, we preliminarily explored the function of the gene. We found that FtsZ depletion is lethal to , resulting in abnormal round cell shape and mini cell formation, suggesting FtsZ's role in maintaining cell shape stability.