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 Stewart, M. D.
Right arrow Articles by Wong, J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Stewart, M. D.
Right arrow Articles by Wong, J.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, September 2006, p. 6890-6901, Vol. 26, No. 18
0270-7306/06/$08.00+0     doi:10.1128/MCB.00948-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Dynamic Regulation of Histone Modifications in Xenopus Oocytes through Histone Exchange

M. David Stewart,1 John Sommerville,2 and Jiemin Wong1*

Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas,1 Division of Cell and Molecular Biology, School of Biology, University of St. Andrews, Scotland, United Kingdom2

Received 29 May 2006/ Accepted 30 June 2006

Histone H3 lysine 9 (H3K9) methylation has broad roles in transcriptional repression, gene silencing, maintenance of heterochromatin, and epigenetic inheritance of heterochromatin. Using Xenopus laevis oocytes, we have previously shown that targeting G9a, an H3K9 histone methyltransferase, to chromatin increases H3K9 methylation and consequently represses transcription. Here we report that treatment with trichostatin A induces histone acetylation and is sufficient to activate transcription repressed by G9a, and this activation is accompanied by a reduction in dimethyl H3K9 (H3K9me2). We tested the possibility that the reduction in H3K9me2 was due to the replacement of methylated H3 with unmethylated H3.3. Surprisingly, we found that both free H3 and H3.3 are continually exchanged with chromatin-associated histones. This dynamic exchange of chromatin-associated H3 with free H3/H3.3 was not affected by alterations in transcriptional activity, elongation, acetylation, H3K9 methylation, or DNA replication. In support of this continual histone exchange model, we show that maintenance of H3K9 methylation at a specific site requires the continual presence of an H3K9 histone methyltransferase. Upon dissociation of the methyltransferase, H3K9 methylation decreases. Taken together, our data suggest that chromatin-associated and non-chromatin-associated histones are continually exchanged in the Xenopus oocyte, creating a highly dynamic chromatin environment.

* Corresponding author. Mailing address: Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030. Phone: (713) 798-6291. E-mail: jwong{at}bcm.tmc.edu.

Molecular and Cellular Biology, September 2006, p. 6890-6901, Vol. 26, No. 18
0270-7306/06/$08.00+0     doi:10.1128/MCB.00948-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Miao, F., Smith, D. D., Zhang, L., Min, A., Feng, W., Natarajan, R. (2008). Lymphocytes From Patients With Type 1 Diabetes Display a Distinct Profile of Chromatin Histone H3 Lysine 9 Dimethylation: An Epigenetic Study in Diabetes. Diabetes 57: 3189-3198 [Abstract] [Full Text]  
  • Seki, Y., Yamaji, M., Yabuta, Y., Sano, M., Shigeta, M., Matsui, Y., Saga, Y., Tachibana, M., Shinkai, Y., Saitou, M. (2007). Cellular dynamics associated with the genome-wide epigenetic reprogramming in migrating primordial germ cells in mice. Development 134: 2627-2638 [Abstract] [Full Text]  


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