The impacts of the Spx regulator and H2O2 stress on the transcriptome of Streptococcus mutans. Streptococcus mutans UA159

As a resident of the oral cavity, Streptococcus mutans must withstand a variety of stresses, including oxidative stress. Previously, we reported the identification of two Spx homologues (SpxA1 and SpxA2) in Streptococcus mutans that appear critical in the ability of the microbe to tolerate oxidative stresses; SpxA1 was shown to play a primary role in activation of detoxification strategies whereas SpxA2 served as a secondary activator. Here, we used RNA deep sequencing (RNA-Seq) to examine the transcriptional changes associated with H2O2 stress in the parent S. mutans strain UA159 and to compare the peroxide-stress transcriptome of UA159 with its Δspx derivatives. The transcriptome data confirmed the relationship between SpxA1 and genes typically associated with oxidative stress responses, but also identified new genes and metabolic pathways that are activated during peroxide stress, also in an SpxA1-dependent manner. Overall design: Transcriptional profiling of Streptococcus mutans UA159 wild-type strain was performed before and after 5 minutes exposure to 0.5mM H2O2, and of mutant strains ∆spxA1, ∆spxA2, ∆spxA1/∆spxA2 after the same H2O2 exposure. RNA was extracted from S. mutans cells after the desired treament using standard methods. Following Dnase treatment and enrichment for mRNA, Deep RNA sequencing was performed by the University of Rochester Genomics Research Center using the Illumina platform