QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Vol. 18, Issue 3, 953-964, March 2007

This Article Full Text Full Text (PDF) Supplemental Material All Versions of this Article: E06-06-0512v1 18/3/953    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bernstein, K. A. Articles by Baserga, S. J. Search for Related Content PubMed PubMed Citation Articles by Bernstein, K. A. Articles by Baserga, S. J.

Ribosome Biogenesis Is Sensed at the Start Cell Cycle Checkpoint

Kara A. Bernstein^*, Franziska Bleichert^*, James M. Bean, Frederick R. Cross^,, and Susan J. Baserga^*,,,||

Departments of Molecular Biophysics and Biochemistry, *Genetics, and ^||Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06520; and Rockefeller University, New York, NY 10021

Submitted June 9, 2006; Revised December 5, 2006; Accepted December 20, 2006
Monitoring Editor: Karsten Weis

In the yeast Saccharomyces cerevisiae it has long been thought that cells must reach a critical cell size, called the "setpoint," in order to allow the Start cell cycle transition. Recent evidence suggests that this setpoint is lowered when ribosome biogenesis is slowed. Here we present evidence that yeast can sense ribosome biogenesis independently of mature ribosome levels and protein synthetic capacity. Our results suggest that ribosome biogenesis directly promotes passage through Start through Whi5, the yeast functional equivalent to the human tumor suppressor Rb. When ribosome biogenesis is inhibited, a Whi5-dependent mechanism inhibits passage through Start before significant decreases in both the number of ribosomes and in overall translation capacity of the cell become evident. This delay at Start in response to decreases in ribosome biogenesis occurs independently of Cln3, the major known Whi5 antagonist. Thus ribosome biogenesis may be sensed at multiple steps in Start regulation. Ribosome biogenesis may thus both delay Start by increasing the cell size setpoint and independently may promote Start by inactivating Whi5.

The online version of this article contains supplemental material at MBC Online (http://www.molbiolcell.org).

These authors contributed equally to this work.

Address correspondence to: Susan Baserga (susan.baserga{at}yale.edu)

This article has been cited by other articles:

				C. R. Houchens, A. Perreault, F. Bachand, and T. J. Kelly Schizosaccharomyces pombe Noc3 Is Essential for Ribosome Biogenesis and Cell Division but Not DNA Replication Eukaryot. Cell, September 1, 2008; 7(9): 1433 - 1440. [Abstract] [Full Text] [PDF]

				S. Kundu-Michalik, M.-A. Bisotti, E. Lipsius, A. Bauche, A. Kruppa, T. Klokow, G. Kammler, and J. Kruppa Nucleolar Binding Sequences of the Ribosomal Protein S6e Family Reside in Evolutionary Highly Conserved Peptide Clusters Mol. Biol. Evol., March 1, 2008; 25(3): 580 - 590. [Abstract] [Full Text] [PDF]

				H. Yamada, C. Horigome, T. Okada, C. Shirai, and K. Mizuta Yeast Rrp14p is a nucleolar protein involved in both ribosome biogenesis and cell polarity RNA, November 1, 2007; 13(11): 1977 - 1987. [Abstract] [Full Text] [PDF]

				I. V. Rosado, D. Kressler, and J. d. l. Cruz Functional analysis of Saccharomyces cerevisiae ribosomal protein Rpl3p in ribosome synthesis Nucleic Acids Res., June 13, 2007; (2007) gkm388v1. [Abstract] [Full Text] [PDF]