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

J. Biol. Chem., Vol. 278, Issue 38, 36128-36138, September 19, 2003

This Article Full Text Full Text (PDF) All Versions of this Article: 278/38/36128    most recent M301069200v1 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 Beck, J. Articles by Nassal, M. Search for Related Content PubMed PubMed Citation Articles by Beck, J. Articles by Nassal, M. Social Bookmarking                      What's this?

Efficient Hsp90-independent in Vitro Activation by Hsc70 and Hsp40 of Duck Hepatitis B Virus Reverse Transcriptase, an Assumed Hsp90 Client Protein^*

Jürgen Beck and Michael Nassal 

From the Department of Internal Medicine II/Molecular Biology, University Hospital Freiburg, Hugstetter Strasse 55, Freiburg D-79106, Germany

Hsp90 is a specialized chaperone that controls the activity of many key regulator proteins such as steroid hormone receptors (SHRs). Hormone binding, and therefore SHR activation, requires Hsp90, which is loaded onto the receptors by a series of events involving Hsp70, Hsp40, Hop, and p23. The reverse transcriptase (RT) of hepatitis B viruses, small DNA-containing viruses that replicate via an RNA intermediate, has been reported to depend similarly on Hsp90 for enzymatic activity. Using an in vitro reconstitution system consisting of recombinant duck hepatitis B virus RT, purified chaperones, and the authentic RNA template D, we demonstrate here that this RT can be activated efficiently by just Hsp40 and Hsc70 plus energy, without the need for Hsp90 or other cofactors. The reaction appears to proceed selectively with the Hdj1 variant of Hsp40 but not Hdj2 or its yeast homolog Ydj1. The primary reaction product is a metastable, RNA binding-competent intermediate that decays quickly in the absence of its cognate RNA but, in its presence, accumulates in an initiation-competent form over several hours. Because deletion of the RNase H domain rendered the protein partly chaperone-independent, the chaperones may be needed indirectly to relieve occlusion of the RNA binding site by this domain. Our results do not exclude that other factors contribute to RT activation in vivo, but they challenge a fundamental SHR-like dependence on Hsp90. Thus Hsc70, mostly known for its role in general protein folding, is able to effect activation of a highly specialized target protein.

Received for publication, January 31, 2003 , and in revised form, June 17, 2003.

^* This work was supported by Deutsche Forschungsgemeinschaft Grant DFG Na154/7-1 and by the Fonds der Chemischen Industrie. 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.

To whom correspondence should be addressed. Tel. and Fax: 49-761-270-3507; E-mail: nassal2{at}ukl.uni-freiburg.de.

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

This article has been cited by other articles:

				H. Wang, S. Kim, and W.-S. Ryu DDX3 DEAD-Box RNA Helicase Inhibits Hepatitis B Virus Reverse Transcription by Incorporation into Nucleocapsids J. Virol., June 1, 2009; 83(11): 5815 - 5824. [Abstract] [Full Text] [PDF]

				R. Gorchakov, N. Garmashova, E. Frolova, and I. Frolov Different Types of nsP3-Containing Protein Complexes in Sindbis Virus-Infected Cells J. Virol., October 15, 2008; 82(20): 10088 - 10101. [Abstract] [Full Text] [PDF]

				F. H. T. Nelissen, A. J. van Gammeren, M. Tessari, F. C. Girard, H. A. Heus, and S. S. Wijmenga Multiple segmental and selective isotope labeling of large RNA for NMR structural studies Nucleic Acids Res., August 1, 2008; 36(14): e89 - e89. [Abstract] [Full Text] [PDF]

				L. Lin, F. Wan, and J. Hu Functional and Structural Dynamics of Hepadnavirus Reverse Transcriptase during Protein-Primed Initiation of Reverse Transcription: Effects of Metal Ions J. Virol., June 15, 2008; 82(12): 5703 - 5714. [Abstract] [Full Text] [PDF]

				M. Stahl, J. Beck, and M. Nassal Chaperones Activate Hepadnavirus Reverse Transcriptase by Transiently Exposing a C-Proximal Region in the Terminal Protein Domain That Contributes to {varepsilon} RNA Binding J. Virol., December 15, 2007; 81(24): 13354 - 13364. [Abstract] [Full Text] [PDF]

				M. Stahl, M. Retzlaff, M. Nassal, and J. Beck Chaperone activation of the hepadnaviral reverse transcriptase for template RNA binding is established by the Hsp70 and stimulated by the Hsp90 system Nucleic Acids Res., September 25, 2007; 35(18): 6124 - 6136. [Abstract] [Full Text] [PDF]

				F. C. Girard, O. M. Ottink, K. A.M. Ampt, M. Tessari, and S. S. Wijmenga Thermodynamics and NMR studies on Duck, Heron and Human HBV encapsidation signals Nucleic Acids Res., April 11, 2007; (2007) gkm131v1. [Abstract] [Full Text] [PDF]

				S. Flodell, M. Petersen, F. Girard, J. Zdunek, K. Kidd-Ljunggren, J. Schleucher, and S. Wijmenga Solution structure of the apical stem-loop of the human hepatitis B virus encapsidation signal Nucleic Acids Res., September 11, 2006; 34(16): 4449 - 4457. [Abstract] [Full Text] [PDF]

				S.-Y. Sohn, S.-B. Kim, J. Kim, and B.-Y. Ahn Negative regulation of hepatitis B virus replication by cellular Hsp40/DnaJ proteins through destabilization of viral core and X proteins J. Gen. Virol., July 1, 2006; 87(7): 1883 - 1891. [Abstract] [Full Text] [PDF]

				E. Frolova, R. Gorchakov, N. Garmashova, S. Atasheva, L. A. Vergara, and I. Frolov Formation of nsP3-Specific Protein Complexes during Sindbis Virus Replication. J. Virol., April 1, 2006; 80(8): 4122 - 4134. [Abstract] [Full Text] [PDF]

				F. Cao, M. P. Badtke, L. M. Metzger, E. Yao, B. Adeyemo, Y. Gong, and J. E. Tavis Identification of an Essential Molecular Contact Point on the Duck Hepatitis B Virus Reverse Transcriptase J. Virol., August 15, 2005; 79(16): 10164 - 10170. [Abstract] [Full Text] [PDF]

				T. Lackner, A. Muller, M. Konig, H.-J. Thiel, and N. Tautz Persistence of Bovine Viral Diarrhea Virus Is Determined by a Cellular Cofactor of a Viral Autoprotease J. Virol., August 1, 2005; 79(15): 9746 - 9755. [Abstract] [Full Text] [PDF]

				M. Yamashita, W. Kamitani, H. Yanai, N. Ohtaki, Y. Watanabe, B.-J. Lee, S. Tsuji, K. Ikuta, and K. Tomonaga Persistent Borna Disease Virus Infection Confers Instability of HSP70 mRNA in Glial Cells during Heat Stress J. Virol., February 15, 2005; 79(4): 2033 - 2041. [Abstract] [Full Text] [PDF]

				S. W. Fewell, C. M. Smith, M. A. Lyon, T. P. Dumitrescu, P. Wipf, B. W. Day, and J. L. Brodsky Small Molecule Modulators of Endogenous and Co-chaperone-stimulated Hsp70 ATPase Activity J. Biol. Chem., December 3, 2004; 279(49): 51131 - 51140. [Abstract] [Full Text] [PDF]

				J. Hu, D. Flores, D. Toft, X. Wang, and D. Nguyen Requirement of Heat Shock Protein 90 for Human Hepatitis B Virus Reverse Transcriptase Function J. Virol., December 1, 2004; 78(23): 13122 - 13131. [Abstract] [Full Text] [PDF]

				K. Hu, J. Beck, and M. Nassal SELEX-derived aptamers of the duck hepatitis B virus RNA encapsidation signal distinguish critical and non-critical residues for productive initiation of reverse transcription Nucleic Acids Res., August 16, 2004; 32(14): 4377 - 4389. [Abstract] [Full Text] [PDF]