The mRNA derived MalH sRNA contributes to alternative carbon source utilization by tuning maltoporin expression in E. coli

Ira Iosub, Marta Marchioretto, Rob Van Nues, Stuart Mckellar, Gabriella Viero, Sander Granneman

Research output: Contribution to journalArticlepeer-review

Abstract

Previous high-throughput studies in Gram-negative bacteria identified a large number of 3’UTR fragments that potentially function as sRNAs. Here we extensively characterise the MalH sRNA. We show that MalH is a stable degradation intermediate derived from the 3’ end of malG, which is part of the maltose uptake operon transcript malEFG. Unlike the majority of bacterial sRNAs, MalH is transiently expressed during the transition from the exponential to the stationary growth phase, suggesting that it contributes to adaptation to changes in nutrient availability. Over-expression of MalH reduces expression of general outer membrane porins and MicA, a repressor of the high-affinity maltose/maltodextrin transporter LamB. Disrupting MalH production and function significantly reduces lamB accumulation when maltose is the only available carbon source, presumably due to the accumulation of the MicA repressor. We propose that MalH is part of a regulatory network that, during the transition phase, directly or indirectly promotes accumulation of high-affinity maltose transporters in the outer membrane by dampening competing pathways.
Original languageEnglish
Pages (from-to)1-18
JournalRna biology
Early online date12 Oct 2020
DOIs
Publication statusE-pub ahead of print - 12 Oct 2020

Keywords

  • non coding RNA
  • E. coli
  • 3’UTR
  • RNA-RNA interactions
  • stress response
  • next generation sequencing

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