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

This Article Full Text (PDF, 177K) 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 Wells, W. A. Search for Related Content PubMed Articles by Wells, W. A. Social Bookmarking                            What's this?

© The Rockefeller University Press, 0021-9525/2001/8/481 $5.00
The Journal of Cell Biology, Volume 154, Number 3, August 6, 2001 481-481

Transcription gets a licence

VP16 needs either Met30 ubiquitin ligase (left) or fused ubiquitin (right) for activity. Tansey/AAA

Ubiquitination of some transcriptional activators may be necessary both to make them functional activators and to signal their destruction, according to a recent study from William Tansey (Cold Spring Harbor Laboratory, Cold Spring Harbor, NY) and colleagues. Tansey suggests that ubiquitination is a temporary licence for transcription that preprograms destruction into the very activation process, thus keeping activators under tight control.

Tansey has been trying to unite the proteolysis and transcription fields ever since he noticed that the determinants of ubiquitination and transcription activation were often overlapping or even inseparable. Selling this idea took some time. "It's counterintuitive," he says. "You have proteins that are destroyed not when they are no longer needed but when they are at their most active. People have some trouble with this idea."

In the new experiments, Tansey found that a specific ubiquitin ligase was necessary for the VP16 transcriptional activation domain to activate transcription, and that this requirement could be circumvented by fusing a single ubiquitin (which does not signal destruction) to the activator.

One thing that ubiquitin may be doing, not necessarily related to actual destruction, is recruiting the proteasome. Stephen Johnson and colleagues (University of Texas Southwestern Medical Center, Dallas, TX) recently reported that the 19S regulatory particle of the proteasome is required for efficient transcription elongation, perhaps in some kind of chaperone role.

As for destruction, Tansey does not know how tightly it is coupled with transcription. "Are transcription factors truly a disposable thing—a one-shot deal?," he asks. Further studies are needed to answer this question and to determine just how many different transcription factors are licensed by this mechanism.

References:

Salghetti, S.E., et al. 2001. Science. 10.1126/science.1062079 http://www.sciencemag.org/cgi/content/abstract/1062079

Ferdous, A., et al. 2001. Mol. Cell. 7:981–991.

William A. Wells

wellsw{at}rockefeller.edu

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

This Article Full Text (PDF, 177K) 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 Wells, W. A. Search for Related Content PubMed Articles by Wells, W. A. Social Bookmarking                            What's this?