HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 282, Issue 43, 31469-31476, October 26, 2007

This Article Full Text Full Text (PDF) All Versions of this Article: 282/43/31469    most recent M706935200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schwartz, A. Articles by Boudvillain, M. Search for Related Content PubMed PubMed Citation Articles by Schwartz, A. Articles by Boudvillain, M. Social Bookmarking                      What's this?

Transcription Termination Factor Rho Can Displace Streptavidin from Biotinylated RNA^*

Annie Schwartz, Emmanuel Margeat, A. Rachid Rahmouni, and Marc Boudvillain¹

From the CNRS UPR4301, Centre de Biophysique Moléculaire, Rue Charles Sadron, 45071 Orléans cedex 2, France and the CNRS UMR5048, Centre de Biochimie Structurale, 29 Rue de Navacelles 34090, Montpellier, France, INSERM U554, 34090, Montpellier, France, Universités Montpellier 1 et 2, 34090 Montpellier, France

In Escherichia coli, binding of the hexameric Rho protein to naked C-rich Rut (Rho utilization) regions of nascent RNA transcripts initiates Rho-dependent termination of transcription. Although the ring-shaped Rho factor exhibits in vitro RNA-dependent ATPase and directional RNA-DNA helicase activities, the actual molecular mechanisms used by Rho to disrupt the intricate network of interactions that cement the ternary transcription complex remain elusive. Here, we show that Rho is a molecular motor that can apply significant disruptive forces on heterologous nucleoprotein assemblies such as streptavidin bound to biotinylated RNA molecules. ATP-dependent disruption of the biotin-streptavidin interaction demonstrates that Rho is not mechanistically limited to the melting of nucleic acid base pairs within molecular complexes and confirms that specific interactions with the roadblock target are not required for Rho to operate properly. We also show that Rho-induced streptavidin displacement depends significantly on the identity of the biotinylated transcript as well as on the position, nature, and length of the biotin link to the RNA chain. Altogether, our data are consistent with a "snow plough" type of mechanism of action whereby an early rearrangement of the Rho-substrate complex (activation) is rate-limiting, physical force (pulling) is exerted on the RNA chain by residues of the central Rho channel, and removal of structural obstacles from the RNA track stems from their nonspecific steric exclusion from the hexamer central hole. In this context, a simple model for the regulation of Rho-dependent termination based on the modulation of disruptive dynamic loading by secondary factors is proposed.

Received for publication, August 20, 2007 , and in revised form, August 27, 2007.

^* This work was supported by grants from the Agence Nationale de la Recherche (Grant PCV06_135253), the Association pour la Recherche sur le Cancer (Grant 3639), and the Ligue contre le Cancer (Région Centre). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ To whom correspondence should be addressed. Tel.: 33-238-25-55-85; Fax: 33-238-63-15-17; E-mail: marc.boudvillain{at}cnrs-orleans.fr.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				C. Mosrin-Huaman, R. Honorine, and A. R. Rahmouni Expression of Bacterial Rho Factor in Yeast Identifies New Factors Involved in the Functional Interplay between Transcription and mRNP Biogenesis Mol. Cell. Biol., August 1, 2009; 29(15): 4033 - 4044. [Abstract] [Full Text] [PDF]

				D. Dutta, J. Chalissery, and R. Sen Transcription Termination Factor Rho Prefers Catalytically Active Elongation Complexes for Releasing RNA J. Biol. Chem., July 18, 2008; 283(29): 20243 - 20251. [Abstract] [Full Text] [PDF]