A novel enrichment strategy reveals unprecedented number of novel transcription start sites at single base resolution in a model prokaryote and the gut microbiome

Abstract

We have developed Cappable-seq that specifically captures primary RNA transcripts by enzymatically modifying the 5 triphosphorylated end of RNA with a selectable tag. We first applied Cappable-seq to E. coli, achieving up to 50 fold enrichment of primary transcripts and identifying an unprecedented 16539 transcription start sites (TSS) genome-wide at single base resolution. We also applied Cappable-seq to a mouse cecum sample and for the first time identified TSS in a microbiome. Furthermore, Cappable-seq universally depletes ribosomal RNA and reduces the complexity of the transcriptome to a single quantifiable tag per TSS enabling digital profiling of gene expression in any microbiome.