MCB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
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 HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Chen, X. L.
Right arrow Articles by Johnson, E. S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Chen, X. L.
Right arrow Articles by Johnson, E. S.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, May 2005, p. 4311-4320, Vol. 25, No. 10
0270-7306/05/$08.00+0     doi:10.1128/MCB.25.10.4311-4320.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Misregulation of 2µm Circle Copy Number in a SUMO Pathway Mutant

Xiaole L. Chen, Alison Reindle, and Erica S. Johnson*

Department of Biochemistry and Molecular Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107

Received 6 October 2004/ Returned for modification 20 November 2004/ Accepted 2 February 2005

Attachment of the ubiquitin-like protein SUMO to other proteins is an essential process in Saccharomyces cerevisiae. However, yeast mutants lacking the SUMO ligases Siz1 and Siz2/Nfi1 are viable, even though they show dramatically reduced levels of SUMO conjugation. This siz1{Delta} siz2{Delta} double mutant is cold sensitive and has an unusual phenotype in that it forms irregularly shaped colonies that contain sectors of wild-type-appearing cells as well as sectors of enlarged cells that are arrested in G2/M. We have found that these phenotypes result from misregulation of the copy number of the endogenous yeast plasmid, the 2µm circle. siz1{Delta} siz2{Delta} mutants have up to 40-fold-higher levels of 2µm than do wild-type strains. Furthermore, 2µm is responsible for the siz1{Delta} siz2{Delta} mutant's obvious growth defects, as siz1{Delta} siz2{Delta} [cir0] strains, which lack 2µm, are no longer heterogeneous and show growth characteristics similar to those of the wild type. Possible mechanisms for SUMO's effect on 2µm are suggested by the finding that both Flp1 recombinase and Rep2, two of the four proteins encoded by 2µm, are covalently modified by SUMO. Our data suggest that SUMO attachment negatively regulates Flp1 levels, which may partially account for the increased 2µm copy number in the siz1{Delta} siz2{Delta} strain.

* Corresponding author. Mailing address: Department of Biochemistry and Molecular Pharmacology, Thomas Jefferson University, 233 South 10th St., BLSB 231, Philadelphia, PA 19107. Phone: (215) 503-4616. Fax: (215) 503-5393. E-mail: Erica.Johnson{at}jefferson.edu.

Molecular and Cellular Biology, May 2005, p. 4311-4320, Vol. 25, No. 10
0022-538X/05/$08.00+0     doi:10.1128/MCB.25.10.4311-4320.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2005 by the American Society for Microbiology. All rights reserved.