Temperature-dependent regulation of the Escherichia coli lpxT gene

Publication date: Available online 9 July 2019Source: Biochimica et Biophysica Acta (BBA) - Gene Regulatory MechanismsAuthor(s): Barbara Sciandrone, Francesca Forti, Sara Perego, Federica Falchi, Federica BrianiAbstractThe Lipid A moiety of the lipopolysaccharide can be covalently modified during its transport to the outer membrane by different enzymes, among which the LpxT inner membrane protein. LpxT transfers a phosphate group from the undecaprenyl pyrophosphate to the Lipid A, a modification affecting the stability of the outer membrane and its recognition by the host immune system in Enterobacteria. We previously found that the expression of the Pseudomonas aeruginosa lpxT gene, encoding LpxT, is induced in response to a temperature upshift and we proposed that an RNA thermometer was responsible for such regulation. Here we show that the Escherichia coli lpxT orthologous gene is down-regulated upon a temperature upshift and investigated the mechanism of this regulation. We found that the LpxT protein stability is not affected by the temperature change. Conversely, the lpxT mRNA levels strongly decrease upon a shift from 28 to 42 °C. The lack of MicA sRNA, which was previously implicated in lpxT regulation, does not affect lpxT thermal regulation. We identified the lpxTp promoter and demonstrated that lpxTp has temperature-sensitive activity depending on its peculiar −10 region. Moreover, we found that RNase E-dependent degradation of the lpxT mRNA is also modulated ...
Source: Biochimica et Biophysica Acta (BBA) Gene Regulatory Mechanisms - Category: Genetics & Stem Cells Source Type: research