This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Alcorlo, M.
Right arrow Articles by Hermoso, J. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Alcorlo, M.
Right arrow Articles by Hermoso, J. M.

 Previous Article  |  Next Article 

Journal of Bacteriology, November 2007, p. 8024-8033, Vol. 189, No. 22
0021-9193/07/$08.00+0     doi:10.1128/JB.01047-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

In Vivo DNA Binding of Bacteriophage GA-1 Protein p6{triangledown}

Martín Alcorlo, Margarita Salas,* and José M. Hermoso

Instituto de Biología Molecular "Eladio Viñuela" (CSIC), Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain

Received 3 July 2007/ Accepted 6 September 2007

Bacteriophage GA-1 infects Bacillus sp. strain G1R and has a linear double-stranded DNA genome with a terminal protein covalently linked to its 5' ends. GA-1 protein p6 is very abundant in infected cells and binds DNA with no sequence specificity. We show here that it binds in vivo to the whole viral genome, as detected by cross-linking, chromatin immunoprecipitation, and real-time PCR analyses, and has the characteristics of a histone-like protein. Binding to DNA of GA-1 protein p6 shows little supercoiling dependency, in contrast to the ortholog protein of the evolutionary related Bacillus subtilis phage {phi}29. This feature is a property of the protein rather than the DNA or the cellular background, since {phi}29 protein p6 shows supercoiling-dependent binding to GA-1 DNA in Bacillus sp. strain G1R. GA-1 DNA replication is impaired in the presence of the gyrase inhibitors novobiocin and nalidixic acid, which indicates that, although noncovalently closed, the viral genome is topologically constrained in vivo. GA-1 protein p6 is also able to bind {phi}29 DNA in B. subtilis cells; however, as expected, the binding is less supercoiling dependent than the one observed with the {phi}29 protein p6. In addition, the nucleoprotein complex formed is not functional, since it is not able to transcomplement the DNA replication deficiency of a {phi}29 sus6 mutant. Furthermore, we took advantage of {phi}29 protein p6 binding to GA-1 DNA to find that the viral DNA ejection mechanism seems to take place, as in the case of {phi}29, with a right to left polarity in a two-step, push-pull process.

* Corresponding author. Mailing address: Instituto de Biología Molecular "Eladio Viñuela" (CSIC), Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma, Cantoblanco, 28049 Madrid, Spain. Phone: 34-914978435. Fax: 34-914978490. E-mail: msalas{at}cbm.uam.es

{triangledown} Published ahead of print on 14 September 2007.

Journal of Bacteriology, November 2007, p. 8024-8033, Vol. 189, No. 22
0021-9193/07/$08.00+0     doi:10.1128/JB.01047-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»