Archaeal chromatin and transcription

SummaryArchaea contain a variety of sequence‐independent DNA binding proteins consistent with the evolution of several different, sometimes overlapping and exchangeable solutions to the problem of genome compaction. Some of these proteins undergo residue‐specific post‐translational lysine acetylation or methylation, hinting at analogues of the histone modifications that regulate eukaryotic chromatin structure and transcription. Archaeal transcription initiation most closely resembles the eukaryotic RNA polymerase II (RNAPII) system, but Archaea do not appear to have homologues of the multisubunit complexes that remodel eukaryotic chromatin and activate RNAPII initiation. In contrast, they have sequence‐specific regulators that repress and perhaps activate archaeal transcription by mechanisms superficially similar to the bacterial paradigm of regulating promoter binding by RNAP. Repressors compete with archaeal TATA‐box binding protein (TBP) and TFB for the TATA‐box and TFB‐recognition elements (BRE) of the archaeal promoter, or with archaeal RNAP for the site of transcription initiation. Transcript‐specific regulation by repressors binding to sites of transcript initiation is consi