Identification of molecular key determinants of the Mycobacterium abscessus smooth and rough morphotypes through transcriptome analyses

In this study, we were interested to get deeper insights into the molecular mechanisms that govern the formation and selection of the different colony morphologies in Mycobacterium abscessus strains, including the potential reversibility of the rough (R) phenotype into a smooth (S) phenotype. We used next generation sequencing (NGS) and micro-array / RNAseq approaches to determine the genome sequences and transcriptomic profiles of three isogenic S/R strain couples of M. abscessus. One clinical isolate strain named CF and two collection strains referred as 19977-AT and 19977-IP. To perform the transcriptomic comparison of the rough variant versus the smooth variant for each M. abscessus strain, a customized micro-array has been manufactured by Agilent (8 x 15k format). The design of oligonucleotides covering all protein coding sequences was done using OligoArray version 2.1 on the basis of the 4920 predicted coding sequences composing the entire M. abscessus genome. The experimental data for each of the 3 strains consisted of 6 hybridizations (3 biological replicates with dye-swap).