Transcriptomic study of single mutants hns, hns2 and double mutans hhahha2 and hnshns2 from enteroaggregative E. coli 042 by RNA-seq

Bacterial genomes encode in many instances more than one copy of genes coding for global modulators. In the Enterobacteriaceae, cells express the global modulator H-NS and its paralogue StpA. The enteroaggregative E. coli strain 042 encodes, in addition to the hns and stpA genes, an additional hns gene. We used RNA-seq to compare the transcriptome of the wt strain and its hns, hns2 and double hns hns2 derivatives, as well as of an hha null mutant (hhahha2). It is well known that the Hha protein co-modulates gene expression with H-NS. The results obtained have shown that the main role of H-NS2 is to modulate a subset of H-NS modulated genes, those that also are targeted by Hha, which are mainly HGT genes. When compared with H-NS, H-NS2 also shows a differential expression level and a different regulatory pattern. Overall design: E. coli 042 and derivative mutants hns, hns2, hnshns2 and hhahha2 mRNA profiles were generated by Illumina RNA-seq. RNA extraction, DNase treatment, evaluation of RNA quality and cDNA libraries for Illumina sequencing were performed by Vertis Biotechnologie AG, Freising-Weihenstephan, Germany. Bacterial cells were grown until O.D.600 of 2,0 in LB medium at 37ºC with 200rpm of agitation. Three replicates were grown from each strain, 1 ml of each replicate was collected and bacterial pellets were maintained at -80ºC. Bacterial pellets were sent to Vertis Biotechnologie AG, Freising-Weihenstephan, Germany in dry ice. E. coli 042 wt was used as genome reference (NC_017626.1) for analysis.