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

This Article Full Text (PDF, 885K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Katsnelson, A. Search for Related Content PubMed Articles by Katsnelson, A. Social Bookmarking                            What's this?

ES cells clean house

Undifferentiated cells in the inner cell mass (green) contain proteins damaged by carbonylation (red). NYSTRÖM/NAS

Malin Hernebring, Thomas Nyström (Göteborg University, Göteborg, Sweden), and colleagues find that mouse embryonic stem (ES) cells do some spring cleaning during differentiation to rid themselves of protein damage.

Protein damage is absent in young tissue but accumulates with age. The authors wondered what prevents run-down proteins from being passed via the germline to a newly developing organism.

To address this issue, the researchers measured carbonylation and advanced glycation end product (AGE) formation—two common types of protein damage—in cultured undifferentiated ES cells. "What's been assumed," says Nyström, "is that the [ES] cells would be miraculously kept free of protein damage." But the group was surprised to find levels of these contamination products equivalent to those found in a middle-aged mouse.

After cultured ES cells differentiated, levels of both damage markers dropped dramatically. In blastocysts, too, proliferating cells of the inner cell mass showed damage, but differentiated cells on the outer surface did not.

The elimination of protein damage was accompanied by a threefold increase in the activity of the 20S proteasome, which was previously implicated in degrading oxidative stress products. Nyström posits that this process cleanses the cellular protein slate. The team is now examining how the proteasome's activity is regulated.

Reference:

Hernebring, M., et al. 2006. Proc. Natl. Acad. Sci. USA. doi:10.1073/pnas.0510944103.[Abstract/Free Full Text]

Alla Katsnelson

akatsnelson{at}fastmail.fm

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

This Article Full Text (PDF, 885K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Katsnelson, A. Search for Related Content PubMed Articles by Katsnelson, A. Social Bookmarking                            What's this?