Abstract
ABSTRACT Previous high-throughput studies in Gram-negative bacteria identified a large number of 3ʹUTR fragments that potentially function as sRNAs. Here we extensively characterize the MalH sRNA. We show that MalH is a stable degradation intermediate derived from the 3ʹ 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.
Highlights
D-galactose, and ribose [5]
We proposed that many of these represent novel 3ʹUTRderived sRNAs that target 5ʹUTRs of mRNAs
This sRNA was of particular interest as it was mainly detected during the transition from late exponential to early stationary phase
Summary
D-galactose, and ribose [5]. These carbon sources are not highlyEfficient adaptation to changing environmental conditions is fundamental to bacterial survival and success. D-galactose, and ribose [5]. Efficient adaptation to changing environmental conditions is fundamental to bacterial survival and success. The environ ments that bacteria naturally encounter typically lack optimal concentrations of nutrients, and available substrates can be found in complex mixtures. Free-living bacteria often have to switch from catabolising one nutrient to another and co-utilize multiple substrates. Nutrient availability and bacterial metabolic strategies are closely linked to viru lence [1,2,3,4]. Understanding bacterial physiology from a systems point of view requires a thorough understanding of how adaptation to changes in nutrient composition in the environment is controlled
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
