RNA polymerase sigma-E factor sigE Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. This sigma factor is required for the synthesis of the antibiotic actinomycin. MAQGEVLEFEEIVRTRQDALLRTPPGLVPDPVDAQDLLQTALARTYGRWEGIADKRLADAYLRRVMINTRTEWWRARKLEEVPTEQLPDARVEDSTEQHADRALLMDAMKVLAPKQRSVVVLRHWEQMSTEETAAALGMSAGTVKSTLHRALARLREELETRDLDARALEREERERCAAA RPOE_STRAT 180