Genome-wide RNA-seq of Bacteroides thetaiotaomicron VPI-5482 with Bacteroides phage challenge

Purpose: Examining the transcriptome of Bacteroides thetaiotaomicron VPI-5482 challenged with Bacteroides phage to assess surface molecule expression changes Methods: Bacteroides thetaiotaomicron was grown in BPRM in vitro or Germ-Free mice were monocolonized with Bacteroides thetaiotaomicron and gavaged with ARB25 phage. Fold change was calculated as live phage versus heat-killed phage treated samples with n=3 biological replicates. Once cells reached an optical density corresponding to mid-log phase growth (absorbance between 0.4-0.5), RNA was isolated and rRNA depleted. Samples were multiplexed for sequencing on the Illumina HiSeq platform at the University of Michigan Sequencing Core. Data was analyzed using Arraystar software (DNASTAR, Inc.) using DEseq2 normalization with default parameters. Genes with significant up- or down-regulation were determined by the following criteria: genes with an average fold-change >5-fold and with at least 2/3 biological replicates with a normalized expression level >1% of the overall average, and a p-value < 0.05 (t test with Benjamini-Hochberg correction) Results: Specific capsule expression was increased in wild-type B. thetaiotaomicron during phage infection in vitro and in vivo. Many corresponding in vivo genes were upregulated as well as other surface layer proteins. rRNA-depleted, mRNA profiles of Bacteroides thetaiotaomicron VPI-5482 grown in vitro or isolated from Germ-Free mice challenged with Bacteroides phage using Heat killed phage as a reference in biological triplicate run on Illumina NextSeq platform.