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 Kobayashi, T.
Right arrow Articles by Horiuchi, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kobayashi, T.
Right arrow Articles by Horiuchi, T.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, January 2001, p. 136-147, Vol. 21, No. 1
0270-7306/01/$04.00+0 DOI: 10.1128/MCB.21.1.136-147.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.

Identification of DNA cis Elements Essential for Expansion of Ribosomal DNA Repeats in Saccharomyces cerevisiae

Takehiko Kobayashi,1,* Masayasu Nomura,2 and Takashi Horiuchi1

National Institute for Basic Biology, Okazaki 444-8585, Japan,1 and Department of Biological Chemistry, University of California, Irvine, Irvine, California 92697-17002

Received 24 August 2000/Accepted 9 October 2000

Saccharomyces cerevisiae carries ~150 ribosomal DNA (rDNA) copies in tandem repeats. Each repeat consists of the 35S rRNA gene, the NTS1 spacer, the 5S rRNA gene, and the NTS2 spacer. The FOB1 gene was previously shown to be required for replication fork block (RFB) activity at the RFB site in NTS1, for recombination hot spot (HOT1) activity, and for rDNA repeat expansion and contraction. We have constructed a strain in which the majority of rDNA repeats are deleted, leaving two copies of rDNA covering the 5S-NTS2-35S region and a single intact NTS1, and whose growth is supported by a helper plasmid carrying, in addition to the 5S rRNA gene, the 35S rRNA coding region fused to the GAL7 promoter. This strain carries a fob1 mutation, and an extensive expansion of chromosomal rDNA repeats was demonstrated by introducing the missing FOB1 gene by transformation. Mutational analysis using this system showed that not only the RFB site but also the adjacent ~400-bp region in NTS1 (together called the EXP region) are required for the FOB1-dependent repeat expansion. This ~400-bp DNA element is not required for the RFB activity or the HOT1 activity and therefore defines a function unique to rDNA repeat expansion (and presumably contraction) separate from HOT1 and RFB activities.

* Corresponding author. Mailing address: National Institute for Basic Biology, 38 Nishigonaka, Myodaijicho, Okazaki 444-8585, Japan. Phone: 81-564-55-7692. Fax: 81-564-55-7695. E-mail: koba{at}nibb.ac.jp.

Molecular and Cellular Biology, January 2001, p. 136-147, Vol. 21, No. 1
0270-7306/01/$04.00+0 DOI: 10.1128/MCB.21.1.136-147.2001
Copyright © 2001, 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 © 2001 by the American Society for Microbiology. All rights reserved.