TRANSCRIPTION - NEW INSIGHTS FROM STUDIES ON ARCHAEA

Molecular-genetic analyses have revealed that the Archaea (archaebacte ria) are phylogenetically distinct front both eukaryotes and eubacteri a. Archaea lack nuclei and resemble eubacteria in morphology and genom ic organization but their molecular design shares many features with e ukaryotes. Here, we review recent work that indicates that the archaea l transcriptional machinery is strikingly similar to the RNA polymeras e I, II and III systems of eukaryotic cell nuclei. These findings prov ide important insights into the evolution of the transcriptional appar atus.