Intrinsic G1 Delay in S. Cerevisiae Daughter Cells

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

A grant has been awarded to Dr Heideman of the University of Wisconsin to study the fundamental processes that allow cells to maintain a constant size. The proposed research will focus on the process by which newly formed yeast cells regulate cell division. The budding yeast, S. cerevisiae, divides by producing newly formed daughter cells. These daughters must delay cell division until they have time to grow to the proper cell size. Dr Heideman's recent results show that cell cycle delay in the newly formed daughter cells is mediated by a protein factor called Ace2 that is specifically located in the nucleus of new daughter cells and excluded from mother cells. In mutant strains that are unable to make Ace2, daughters enter the cell cycle prematurely and divide at a smaller than normal cell size. The proposed research will study the connections between Ace2 and the production of a protein called Cln3 that regulates the rate of cell division. Cln3 is a member of a family of key cell cycle regulatory proteins called cyclins. Cyclins are found in all higher organisms. The proposed research will determine how Ace2 regulates the level of the messenger RNA that encodes Cln3. This work will involve time-lapse digital microscopy, molecular genetics, and the use of genomic tools that have recently become available. This research is aimed at a fundamental question in biology: How do cells balance growth in size with cell division? This process is clearly a part of all cellular life, since organisms throughout the biological world are able to maintain a constant cell size. The research focuses on budding yeast, one of the simplest and most readily understood eukaryotic organisms. Work in yeast has historically yielded very rapid progress, especially in the field of cell cycle research. Because the basic machinery of cell cycle control remains conserved among eukaryotes, this work will have relevance to understanding how other organisms maintain cell size as well. In addition, the project will provide research training for graduate and undergraduate students, as well as hands on research experience for undergraduate and high school students in summer programs targeting under-represented minority students