The holoenzyme of prokaryotic RNA polymerase consists of the core enzyme, made of two 𝛼, 𝛽, 𝛽’ and 𝜔 subunits, which lacks promoter selectivity and a sigma (𝜎) subunit which enables the core enzyme to initiate transcription in a promoter dependent fashion. A stress sigma factor 𝜎s, in prokaryotes seems to regulate several stress response genes in conjunction with other stress specific regulators. Since the basic principles of transcription are conserved from simple bacteria to multicellular complex organisms, an obvious question is: what is the identity of a counterpart of 𝜎s, that is closest to the core polymerase and that dictates transcription of stress regulated genes in general? In this review, we discuss the logic behind the suggestion that like in prokaryotes, eukaryotes also have a common functional unit in the transcription machinery through which the stress specific transcription factors regulate rapid and highly controlled induction of gene expression associated with generalized stress response and point to some candidates that would fit the bill of the eukaryotic 𝜎s.
Volume 44 | Issue 6
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