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 Weiss, K.
Right arrow Articles by Simpson, R. T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Weiss, K.
Right arrow Articles by Simpson, R. T.

Molecular and Cellular Biology, September 1998, p. 5392-5403, Vol. 18, No. 9
0270-7306/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

High-Resolution Structural Analysis of Chromatin at Specific Loci: Saccharomyces cerevisiae Silent Mating Type Locus HMLalpha

Kerstin Weiss and Robert T. Simpson*

Department of Biochemistry and Molecular Biology, The Center for Gene Regulation, The Pennsylvania State University, University Park, Pennsylvania 16802

Received 5 March 1998/Returned for modification 21 April 1998/Accepted 4 June 1998

Genetic studies have suggested that chromatin structure is involved in repression of the silent mating type loci in Saccharomyces cerevisiae. Chromatin mapping at nucleotide resolution of the transcriptionally silent HMLalpha and the active MATalpha shows that unique organized chromatin structure characterizes the silent state of HMLalpha . Precisely positioned nucleosomes abutting the silencers extend over the alpha 1 and alpha 2 coding regions. The HO endonuclease recognition site, nuclease hypersensitive at MATalpha , is protected at HMLalpha . Although two precisely positioned nucleosomes incorporate transcription start sites at HMLalpha , the promoter region of the alpha 1 and alpha 2 genes is nucleosome free and more nuclease sensitive in the repressed than in the transcribed locus. Mutations in genes essential for HML silencing disrupt the nucleosome array near HML-I but not in the vicinity of HML-E, which is closer to the telomere of chromosome III. At the promoter and the HO site, the structure of HMLalpha in Sir protein and histone H4 N-terminal deletion mutants is identical to that of the transcriptionally active MATalpha . The discontinuous chromatin structure of HMLalpha contrasts with the continuous array of nucleosomes found at repressed a-cell-specific genes and the recombination enhancer. Punctuation at HMLalpha may be necessary for higher-order structure or karyoskeleton interactions. The unique chromatin architecture of HMLalpha may relate to the combined requirements of transcriptional repression and recombinational competence.

* Corresponding author. Mailing address: Department of Biochemistry and Molecular Biology, The Center for Gene Regulation, The Pennsylvania State University, University Park, PA 16802. Phone: (814) 863-0276. Fax: (814) 863-7024. E-mail: RTS4{at}PSU.EDU.

Molecular and Cellular Biology, September 1998, p. 5392-5403, Vol. 18, No. 9
0270-7306/98/$04.00+0
Copyright © 1998, 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 © 1998 by the American Society for Microbiology. All rights reserved.