Determinants of transcription initiation by archaeal RNA polymerase.

Transcription in Archaea is catalyzed by an RNA polymerase that is most similar to eukaryotic RNA polymerases both in subunit composition and in transcription initiation factor requirements. Recent studies on archaeal transcription in diverse members of this domain have contributed new details concerning the functions of promoters and transcription factors in guiding initiation by RNA polymerase, and phylogenetic arguments have allowed modeling of archaeal transcription initiation complexes by comparison with recently described models of eukaryotic and bacterial transcription initiation complexes. Important new advances in reconstitution of archaeal transcription complexes from fully recombinant components is permitting testing of hypotheses derived from and informed by these structural models, and will help bring the study of archaeal transcription to the levels of understanding currently enjoyed by bacterial and eukaryotic RNA polymerase II transcription.