A novel archaeal regulatory protein, Sta1, activates transcription from viral promoters. - Analytical Methods & Tools for Lyophilization

A novel archaeal regulatory protein, Sta1, activates transcription from viral promoters.
Received March 17, 2006; Revised June 30, 2006; Accepted July 3, 2006.
Published online 2006 August 14
Alexandra Kessler,1,4 Guennadi Sezonov,1 J. I?aki Guijarro,2 Nicole Desnoues,1 Thierry Rose,3 Muriel Delepierre,2 Stephen D. Bell,5 and David Prangishvili1*
Nucleic Acids Res. 2006 October;
PubMed Central
Copyright ? 2006 The Author(s)
1Unit? de Biologie Mol?culaire du G?ne chez les Extr?mophiles, Institut Pasteur, 25-28 rue du Dr Roux, 75724 Paris Cedex 15, France
2Unit? de RMN des Biomol?cules (CNRS URA 2185), Institut Pasteur, 25-28 rue du Dr Roux, 75724 Paris Cedex 15, France
3Unit? d'Immunog?n?tique Cellulaire, Institut Pasteur, 25-28 rue du Dr Roux, 75724 Paris Cedex 15, France
4Department of Microbiology, University of Regensburg, Universit?ts strasse, 31, D-93053 Regensburg, Germany
5MRC Cancer Cell Unit Hutchison/MRC Research Centre, Hills Road, Cambridge CB2 2XZ, UK
*To whom correspondence should be addressed. Tel: +33 144 38 9119; Fax: +33 145 68 8834; Email: prangish@pasteur.fr
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
While studying gene expression of the rudivirus SIRV1 in cells of its host, the hyperthermophilic crenarchaeon Sulfolobus, a novel archaeal transcriptional regulator was isolated. The 14 kDa protein, termed Sulfolobus transcription activator 1, Sta1, is encoded on the host chromosome. Its activating effect on transcription initiation from viral promoters was demonstrated in in vitro transcription experiments using a reconstituted host system containing the RNA polymerase, TATA-binding protein (TBP) and transcription factor B (TFB). Most pronounced activation was observed at low concentrations of either of the two transcription factors, TBP or TFB. Sta1 was able to bind viral promoters independently of any component of the host pre-initiation complex. Two binding sites were revealed by footprinting, one located in the core promoter region and the second ~30 bp upstream of it. Comparative modeling, NMR and circular dichroism of Sta1 indicated that the protein contained a winged helix?turn?helix motif, most probably involved in DNA binding. This strategy of the archaeal virus to co-opt a host cell regulator to promote transcription of its genes resembles eukaryal virus?host relationships.
Complete article may be viewed online.