Stress profile elicited by trehalose-6-phosphate accumulation in Mycobacterium tuberculosis

The otsB2 gene encoding trehalose-6-phosphate phosphatase is essential for in vitro growth of Mycobacterium tuberculosis and required to establish an acute infection in mice. Essentiality of otsB2 is due to direct or indirect toxic effects associated with the substrate trehalose-6-phosphate that accumulates when OtsB2 gene expression is impaired. In order to gain insight into the molecular basis of trehalose-6-phosphate mediated toxic effects, whole genome transcriptome profiling was done using RNA-seq. A conditional otsB2 mutant of Mycobacterium tuberculosis was generated by inserting an anhydrotetracycline-inducible promoter cassette upstream of the otsB2 start codon,and the transcriptome profile of a fully induced mutant resembling the wildtype phenotype was compared to that of a partially silenced mutant under conditions where 30% residual growth relative to the fully induced mutant was observed. Overall design: Three biological replicates of each the fully induced (at 200 ng/ml anhydrotetracycline) and the partially silenced (at 30 ng/ml anhydrotetracycline) conditional Mycobacterium tuberculosis otsB2 mutant were analyzed