A high-resolution map of bacteriophage ϕX174 transcription.

Bacteriophage ϕX174 is a model virus for studies across the fields of structural biology, genetics, gut microbiomics, and synthetic biology, but did not have a high-resolution transcriptome until this work. In this study we used next-generation sequencing to measure the RNA produced from ϕX174 while infecting its host E. coli C. We broadly confirm the past transcriptome model while revealing several interesting deviations from previous knowledge. Additionally, we measure the strength of canonical ϕX174 promoters and terminators and discover both a putative new promoter that may be activated by heat shock sigma factors, as well as rediscover a controversial Rho-dependent terminator. We also provide evidence for the first antisense transcription observed in the Microviridae, identify two promoters that may be involved in generating this transcriptional activity, and discuss possible reasons why this RNA may be produced.