High-resolution RNA 3'-ends mapping of bacterial Rho-dependent transcripts

Nucleic Acids Res. 2018 Jul 27;46(13):6797-6805. doi: 10.1093/nar/gky274.

Abstract

Transcription termination in bacteria can occur either via Rho-dependent or independent (intrinsic) mechanisms. Intrinsic terminators are composed of a stem-loop RNA structure followed by a uridine stretch and are known to terminate in a precise manner. In contrast, Rho-dependent terminators have more loosely defined characteristics and are thought to terminate in a diffuse manner. While transcripts ending in an intrinsic terminator are protected from 3'-5' exonuclease digestion due to the stem-loop structure of the terminator, it remains unclear what protects Rho-dependent transcripts from being degraded. In this study, we mapped the exact steady-state RNA 3' ends of hundreds of Escherichia coli genes terminated either by Rho-dependent or independent mechanisms. We found that transcripts generated from Rho-dependent termination have precise 3'-ends at steady state. These termini were localized immediately downstream of energetically stable stem-loop structures, which were not followed by uridine rich sequences. We provide evidence that these structures protect Rho-dependent transcripts from 3'-5' exonucleases such as PNPase and RNase II, and present data localizing the Rho-utilization (rut) sites immediately downstream of these protective structures. This study represents the first extensive in-vivo map of exact RNA 3'-ends of Rho-dependent transcripts in E. coli.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Escherichia coli / genetics*
  • Escherichia coli Proteins / metabolism*
  • Nucleic Acid Conformation
  • RNA Stability
  • RNA, Messenger / chemistry*
  • RNA, Messenger / metabolism
  • Sequence Analysis, RNA
  • Terminator Regions, Genetic*
  • Transcription Termination, Genetic*

Substances

  • Escherichia coli Proteins
  • RNA, Messenger
  • Rho protein, E coli