Small RNAs and DNA repair in Mycobacterium tuberculosis adaptive responses

The incidence of tuberculosis (TB) is re-emerging as a public health problem worldwide. Strikingly, only meagre efforts have been invested in this field despite increasing numbers of resistant Mycobacterium tuberculosis (Mtb) strains. To combat this growing problem, we have addressed the molecular mechanisms for Mtb adaptability and genome maintenance. We have pursued the hypothesis that the current TB epidemic is fuelled by the evolution of increasingly resistant variants of Mtb, driven by sub-optimal application of its control measures, namely BCG vaccination and anti-TB treatment. As TB drug treatments apply selective pressure, we postulated that hypermutating strains are likely to emerge under these stress conditions, perpetuating the selection of multidrug resistant (MDR-) and extensively drug-resistant (XDR-) Mtb strains. Based on this rationale, we have defined the global Mtb transcriptome constitutively and under genotoxic stress and searched for responses in genes encoding proteins and small RNAs We have for the first time characterized important Mtb helicases that unwind DNA, namely Ercc3, DinG and RecG. Our biochemical studies have identified several distinguishing features of Mtb helicases, such as the discovery that the DNA strand directionality of Mtb DinG is opposite of that in E. coli. The small RNAs and helicase targets have in common that they are stress-induced and functionally critical for maintaining Mtb genome integrity and fitness for survival under challenging conditions. By using state-of-the-art bioinformatics, molecular and genetic approaches, we have discovered novel helicase traits and novel non-coding RNAs (ncRNAs), explaining how and why Mtb mutations occur. Thereby, we have targeted the fundamental forces driving TB drug resistance development. The TBadapt project has generated novel insight into Mtb genome and RNome dynamics, providing significant information required to control this major pathogen in the future.

The incidence of tuberculosis is re-emerging as a public health problem worldwide with a majority of cases in developing countries. Strikingly, only meagre efforts have been invested in this field despite the emergence of increasingly resistant strains of Mycobacterium tuberculosis (Mtb). To combat this growing problem, we seek to understand the molecular mechanisms for adaptability and genome maintenance in intracellular survival of Mtb. We will pursue the hypothesis that the current TB epidemic is fuell ed by the evolution of increasingly resistant variants of Mtb, driven by sub-optimal application of its control measures, namely BCG vaccination and anti-TB treatment. As TB drug treatments apply selective pressure, we postulate that hypermutating strains are likely to emerge under these stress conditions, perpetuating the selection of multidrug resistant (MDR-) and extensively drug-resistant (XDR-) Mtb strains. Genome sequencing of Mtb has revealed the potential proteins and genetic diversity of this pre valent human pathogen, yet little is known about its genome dynamics, transcriptional organization and noncoding RNA output. Based on this rationale, we will define the global Mtb transcriptome and search for small RNAs as well as characterize selected im portant Mtb helicases which are not previously characterized, namely DinG and RecG. The small RNAs and helicase targets have in common that they are stress-induced and functionally critical for maintaining Mtb genome integrity and adaptation under challen ging conditions. By using state-of-the-art bioinformatics, molecular and genetic approaches, characterisation of Mtb helicases and small RNA will be performed. Thereby, we will target the fundamental forces driving TB drug resistance development. The outc ome will be novel insight into the dynamics of Mtb transcriptomics and genome maintenance, providing significant novel information required to control this major pathogen in the coming decades.