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

J. Biol. Chem., Vol. 281, Issue 36, 26491-26500, September 8, 2006

This Article Full Text Full Text (PDF) All Versions of this Article: 281/36/26491    most recent M603982200v1 Alert me when this article is cited 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 Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pani, B. Articles by Sen, R. Search for Related Content PubMed PubMed Citation Articles by Pani, B. Articles by Sen, R. Social Bookmarking                      What's this?

Mechanism of Inhibition of Rho-dependent Transcription Termination by Bacteriophage P4 Protein Psu^*

From the Laboratory of Transcription Biology, Centre For DNA Fingerprinting and Diagnostics, ECIL Road, Nacharam, Hyderabad-500076, India

Psu, a coat protein from bacteriophage P4, has been shown to inhibit Rho-dependent transcription termination in vivo. Co-overexpression of Psu and Rho led to the loss of viability of the cells, which is the consequence of the anti-Rho activity of the protein. The antitermination property of Psu is abolished either by the deletion of 10 or 20 amino acids from its C terminus or by a mutation, Y80C, in Rho. All these experiments indicated probable interactions between Rho and Psu. Purified Psu protein is -helical in nature and appeared to be a dimer. Co-purification of Rho and wild-type Psu on an affinity matrix and co-elution of both of them in Superose-6 gel filtration suggests a direct association of these proteins, whereas a C terminus 10-amino acid deletion derivative of Psu failed to be pulled down in this assay. This indicates that the loss of the function of these mutants is correlated with their inability to interact with each other. In vitro termination assays revealed that Psu can inhibit Rho-dependent termination specifically in a concentration-dependent manner. The presence of Psu affected the affinity of ATP and reduced the rate of ATPase activity of Rho but did not affect either primary or secondary RNA binding activities. In the presence of Psu, Rho was also observed to release RNA very slowly from a stalled elongation complex. We propose that Psu inhibits Rho-dependent termination by slowing down the translocation of Rho along the RNA because of its slow ATPase activity.

Received for publication, April 26, 2006 , and in revised form, June 21, 2006.

^* This work was supported in part by a Wellcome Trust senior research fellowship (to R. S.) and by Centre for DNA Fingerprinting and Diagnostics intra-mural grants. 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 University Grants Commission (UGC) senior research fellow.

² UGC junior research fellow.

³ To whom correspondence should be addressed: Laboratory of Transcription Biology, Centre For DNA Fingerprinting and Diagnostics, ECIL Rd., Nacharam, Hyderabad-500076, India. Tel.: 91-40-27151344 (ext: 1401) Fax: 91-40-27155610; E-mail: rsen{at}cdfd.org.in.

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

This article has been cited by other articles:

				P. Gutierrez, G. Kozlov, L. Gabrielli, D. Elias, M. J. Osborne, I. E. Gallouzi, and K. Gehring Solution Structure of YaeO, a Rho-specific Inhibitor of Transcription Termination J. Biol. Chem., August 10, 2007; 282(32): 23348 - 23353. [Abstract] [Full Text] [PDF]