JCB logo
amgmicro.com
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

Published online 4 September 2000. doi:10.1083/jcb.150.5.1189
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 471K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Rasmussen, T. P.
Right arrow Articles by Jaenisch, R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Rasmussen, T. P.
Right arrow Articles by Jaenisch, R.
Right arrowPubmed/NCBI databases
*Compound via MeSH
*Substance via MeSH
Hazardous Substances DB
*CYTOCHALASIN B
Medline Plus Health Information
*Stem Cells
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

© The Rockefeller University Press, 0021-9525/2000//1189 $5.00
The Journal of Cell Biology, Volume 150, Number 5, , 2000 1189-1198


Report

Dynamic Relocalization of Histone Macroh2a1 from Centrosomes to Inactive X Chromosomes during X Inactivation



Theodore P. Rasmussena, Mary-Ann Mastrangeloa, Amir Edena, John R. Pehrsonb, and Rudolf Jaenischa,c

a Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142
b University of Pennsylvania Veterinary School, Philadelphia, Pennsylvania 19104-6048
c Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139.(617) 258-6505(617) 258-5186

jaenisch{at}wi.mit.edu

Histone variant macroH2A1 (macroH2A1) contains an NH2-terminal domain that is highly similar to core histone H2A and a larger COOH-terminal domain of unknown function. MacroH2A1 is expressed at similar levels in male and female embryonic stem (ES) cells and adult tissues, but a portion of total macroH2A1 protein localizes to the inactive X chromosomes (Xi) of differentiated female cells in concentrations called macrochromatin bodies. Here, we show that centrosomes of undifferentiated male and female ES cells harbor a substantial store of macroH2A1 as a nonchromatin-associated pool. Greater than 95% of centrosomes from undifferentiated ES cells contain macroH2A1. Cell fractionation experiments confirmed that macroH2A1 resides at a pericentrosomal location in close proximity to the known centrosomal proteins {gamma}-tubulin and Skp1. Retention of macroH2A1 at centrosomes was partially labile in the presence of nocodazole suggesting that intact microtubules are necessary for accumulation of macroH2A1 at centrosomes. Upon differentiation of female ES cells, Xist RNA expression became upregulated and monoallelic as judged by fluorescent in situ hybridization, but early Xist signals lacked associated macroH2A1. Xi acquired macroH2A1 soon thereafter as indicated by the colocalization of Xist RNA and macroH2A1. Accumulation of macroH2A1 on X chromosomes occurred with a corresponding loss of centrosomal macroH2A1. Our results define a sequence for the loading of macroH2A1 on the Xi and place this event in the context of differentiation and Xist expression. Furthermore, these results suggest a role for the centrosome in the X inactivation process.

Key Words: Xist • stem cells • chromatin • microtubule • dosage compensation



© 2000 The Rockefeller University Press

Abbreviations used in this paper: ES cell, embryonic stem cell; FISH, fluorescent in situ hybridization; MCB, macrochromatin body; MEF, mouse embryonic fibroblast; QCIF, quantitative centrosome immunofluorescence; Xi, inactive X chromosomes.



Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents