Project description:Transcriptome analysis of NTHi 86-028NPrpsL, NTHi 86-028NPrpsL∆fur, and NTHi 86-028NPrpsL∆fur(pT-fur) strains Nontypeable Haemophilus influenzae (NTHi) is a commensal microorganism of the normal human nasopharyngeal flora, yet also an opportunistic pathogen of the upper and lower respiratory tracts. Changes in gene expression patterns in response to host microenvironments are likely critical for survival. One such system of gene regulation is the ability to carefully regulate iron uptake. A central regulatory system that controls iron uptake, mediated by the ferric uptake regulator Fur, is present in multiple bacteria, including NTHi. To understand the regulation of iron homeostasis in NTHi, fur was deleted in the NTHi strain 86-028NPrpsL. Using RNA-Seq, we identified both protein-encoding and small RNA genes whose expression was repressed or activated by Fur. Overall design: These data comprise transcriptional anaylses of an rpsL mutant of 86-028NP, an isogenic fur mutant of 86-028NPrpsL and a complemented fur mutant strain. All strains were grown in defined medium containing 10 µg/ml human hemoglobin to mid-log phase. Cells were then harvested and RNA extracted. A total of three biological replicates were generated for these analyses. Analysis of transcriptomes using the Illumina HiSeq 2000 of three strains of nontypeable Haemophilus influenzae which include NTHi 86-028NPrpsL, NTHi 86-028NPrpsL∆fur, and NTHi 86-028NPrpsL∆fur(pT-fur) strains. For each strain three biological replicates were analyzed
Project description:Regulatory elements that dictate how Haemophilus influenzae adapts to the airways of COPD patients are poorly understood. In this work, global fitness profiling of H. influenzae mutants by transposon mutagenesis/sequencing (Tn-seq) within the mouse lung identified Dam methyltransferase as an in vivo requirement, even though dam mutants grow normally during in vitro culture. In turn, methylation sequencing found that genome-wide Dam methylation patterns were undermethylated at GATC motifs with putative regulatory elements. This was confirmed for the htpG heat-shock chaperone gene, making it the first case of phenotypic variation controlled by variable Dam methylation for H. influenzae. Moreover, RNA sequencing revealed a novel multifactorial regulatory network, in which Dam methyltransferase activity is coordinated with the FNR and Fur transcriptional regulators to control the expression anaerobic defences against host-produced reactive species. Our results indicate key bacterial pathways for survival in diseased environments with high nitrosative stress, where damage to the airways reduces the amount of oxygen in the lungs as is encountered in COPD.
