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

 Previous Article  |  Next Article 

Mol. Cell. Biol., 12 1997, 7061-7068, Vol 17, No. 12
Copyright © 1997, American Society for Microbiology

The yeast silent information regulator Sir4p anchors and partitions plasmids

A Ansari and MR Gartenberg
Department of Pharmacology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway 08854, USA.

Circular plasmids containing telomeric TG1-3 arrays or the HMR E silencer segregate efficiently between dividing cells of the yeast Saccharomyces cerevisiae. Subtelomeric X repeats augment the TG1-3 partitioning activity by a process that requires the SIR2, SIR3, and SIR4 genes, which are also required for silencer-based partitioning. Here we show that targeting Sir4p to DNA directly via fusion to the bacterial repressor LexA confers efficient mitotic segregation to otherwise unstable plasmids. The Sir4p partitioning activity resides within a 300-amino-acid region (residues 950 to 1262) which precedes the coiled-coil dimerization motif at the extreme carboxy end of the protein. Using a topology-based assay, we demonstrate that the partitioning domain also retards the axial rotation of LexA operators in vivo. The anchoring and partitioning properties of LexA-Sir4p chimeras persist despite the loss of the endogenous SIR genes, indicating that these functions are intrinsic to Sir4p and not to a complex of Sir factors. In contrast, inactivation of the Sir4p- interacting protein Rap1p reduces partitioning by a LexA-Sir4p fusion. The data are consistent with a model in which the partitioning and anchoring domain of Sir4p (PAD4 domain) attaches to a nuclear component that divides symmetrically between cells at mitosis; DNA linked to Sir4p by LexA serves as a reporter of protein movement in these experiments. We infer that the segregation behavior of telomere- and silencer-based plasmids is, in part, a consequence of these Sir4p- mediated interactions. The assays presented herein illustrate two novel approaches to monitor the intracellular dynamics of nuclear proteins.

This article has been cited by other articles:

• Brady, T. L., Fuerst, P. G., Dick, R. A., Schmidt, C., Voytas, D. F. (2008). Retrotransposon Target Site Selection by Imitation of a Cellular Protein. Mol. Cell. Biol. 28: 1230-1239 [Abstract] [Full Text]  
• Dubey, R. N., Gartenberg, M. R. (2007). A tDNA establishes cohesion of a neighboring silent chromatin domain. Genes Dev. 21: 2150-2160 [Abstract] [Full Text]  
• Chiani, F., Felice, F. D., Camilloni, G. (2006). SIR2 modifies histone H4-K16 acetylation and affects superhelicity in the ARS region of plasmid chromatin in Saccharomyces cerevisiae. Nucleic Acids Res 34: 5426-5437 [Abstract] [Full Text]  
• Sears, J., Ujihara, M., Wong, S., Ott, C., Middeldorp, J., Aiyar, A. (2004). The Amino Terminus of Epstein-Barr Virus (EBV) Nuclear Antigen 1 Contains AT Hooks That Facilitate the Replication and Partitioning of Latent EBV Genomes by Tethering Them to Cellular Chromosomes. J. Virol. 78: 11487-11505 [Abstract] [Full Text]  
• Papacs, L. A., Sun, Y., Anderson, E. L., Sun, J., Holmes, S. G. (2004). REP3-Mediated Silencing in Saccharomyces cerevisiae. Genetics 166: 79-87 [Abstract] [Full Text]  
• Kapoor, P., Frappier, L. (2003). EBNA1 Partitions Epstein-Barr Virus Plasmids in Yeast Cells by Attaching to Human EBNA1-Binding Protein 2 on Mitotic Chromosomes. J. Virol. 77: 6946-6956 [Abstract] [Full Text]  
• Andrulis, E. D., Zappulla, D. C., Ansari, A., Perrod, S., Laiosa, C. V., Gartenberg, M. R., Sternglanz, R. (2002). Esc1, a Nuclear Periphery Protein Required for Sir4-Based Plasmid Anchoring and Partitioning. Mol. Cell. Biol. 22: 8292-8301 [Abstract] [Full Text]  
• Xie, W., Gai, X., Zhu, Y., Zappulla, D. C., Sternglanz, R., Voytas, D. F. (2001). Targeting of the Yeast Ty5 Retrotransposon to Silent Chromatin Is Mediated by Interactions between Integrase and Sir4p. Mol. Cell. Biol. 21: 6606-6614 [Abstract] [Full Text]  
• Bennett, C. B., Snipe, J. R., Westmoreland, J. W., Resnick, M. A. (2001). SIR Functions Are Required for the Toleration of an Unrepaired Double-Strand Break in a Dispensable Yeast Chromosome. Mol. Cell. Biol. 21: 5359-5373 [Abstract] [Full Text]  
• Li, Y.-C., Cheng, T.-H., Gartenberg, M. R. (2001). Establishment of Transcriptional Silencing in the Absence of DNA Replication. Science 291: 650-653 [Abstract] [Full Text]  
• Sathyanarayana, U. G., Freeman, L. A., Lee, M.-S., Garrard, W. T. (1999). RNA Polymerase-specific Nucleosome Disruption by Transcription in Vivo. J. Biol. Chem. 274: 16431-16436 [Abstract] [Full Text]  
• Ilves, I., Kivi, S., Ustav, M. (1999). Long-Term Episomal Maintenance of Bovine Papillomavirus Type 1 Plasmids Is Determined by Attachment to Host Chromosomes, Which Is Mediated by the Viral E2 Protein and Its Binding Sites. J. Virol. 73: 4404-4412 [Abstract] [Full Text]  
• Park, P. U., Defossez, P.-A., Guarente, L. (1999). Effects of Mutations in DNA Repair Genes on Formation of Ribosomal DNA Circles and Life Span in Saccharomyces cerevisiae. Mol. Cell. Biol. 19: 3848-3856 [Abstract] [Full Text]  
• Weiss, K., Simpson, R. T. (1998). High-Resolution Structural Analysis of Chromatin at Specific Loci: Saccharomyces cerevisiae Silent Mating Type Locus HMLalpha. Mol. Cell. Biol. 18: 5392-5403 [Abstract] [Full Text]