Project description:The global transcriptional profile of novel T7-like Pseudomonas aeruginosa phage LUZ100 was obtained using the long read RNA sequencing technique ONT-cappable-seq. Using this approach we obtained a comprehensive genome-wide map of viral transcription start sites, terminators and transcription units and gained new insights in the molecular mechanisms of transcriptional regulation of T7-like temperate phages.
Project description:Several temperate actinobacteriophages have been identified that lack integration machinery and instead have genes with predicted partitioning functions. The goal of this sequencing project was to measure transcription levels of these extrachromosomal phages during different stages of their lifecycle, including lysogeny, early infection (30 minutes), and late infection (2 hours 30 minutes), in order to study which genes contribute to extrachromosomal stability.
Project description:LF82, an adherent invasive Escherichia coli (AIEC) pathobiont, is associated with Crohn’s disease, an inflammatory bowel disease of unknown etiology. No genetic features have been identified that distinguish AIEC strains, such as LF82, from “commensal” or pathogenic E. coli. We investigated an extremely rare single nucleotide polymorphism (SNP) within the highly conserved rpoD gene, encoding sigma70 [primary sigma factor, RNA polymerase (RNAP)]. We demonstrate that sigma70 D445V results in transcriptome and phenotypic changes consistent with LF82 phenotypes, including increased biofilm formation and antibiotic resistance. The position of D445V within RNAP is predicted to affect spacer interaction; in vitro transcriptions reveal that the variant increases transcription from several promoters with a 16 bp spacer and a -14G:C. Our work demonstrates that a single SNP within the bacterial primary sigma can lead to myriad gene expression changes/ new phenotypes and suggests an underrecognized mechanism by which pathobionts and other strain variants can emerge.