RpoE

The gene rpoE (RNA polymerase, extracytoplasmic E) encodes the sigma factor sigma-24 (σ24, sigma E, or RpoE), a protein in Escherichia coli^[1] and other species of bacteria. Depending on the bacterial species, this gene may be referred to as sigE.^[2]

RpoE appears to be necessary for the exocytoplasmic stress response. E. coli mutants without rpoE cannot grow at high temperatures (that is, above 42 degrees C)^[3] and show growth defects at lower temperatures, though this may be due to compensatory mutations.^[4] In some bacterial species, such as Clostridium botulinum, this sigma factor may be necessary for sporulation.^[5]

The stress response regulation activities of RpoE are modulated by the Hfq protein in E. coli.^[6]