Discovery notes

Orthologs of the small RPB8 subunit of the eukaryotic RNA polymerases are conserved in hyperthermophilic Crenarchaeota and "Korarchaeota"

Eugene V Koonin¹ , Kira S Makarova¹ and James G Elkins²

¹  National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA

²  Microbial Ecology and Physiology Group, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

author email corresponding author email

Biology Direct 2007, 2:38doi:10.1186/1745-6150-2-38

Published:	14 December 2007

Abstract

Although most of the key components of the transcription apparatus, and in particular, RNA polymerase (RNAP) subunits, are conserved between archaea and eukaryotes, no archaeal homologs of the small RPB8 subunit of eukaryotic RNAP have been detected. We report that orthologs of RPB8 are encoded in all sequenced genomes of hyperthermophilic Crenarchaeota and a recently sequenced "korarchaeal" genome, but not in Euryarchaeota or the mesophilic crenarchaeon Cenarchaeum symbiosum. These findings suggest that all 12 core subunits of eukaryotic RNAPs were already present in the last common ancestor of the extant archaea.

Open peer review

This article was reviewed by Purificacion Lopez-Garcia and Chris Ponting.