Regulation of gene expression is essential for many biological processes. Binding of transcription factors to DNA is a key regulatory step in the control of gene expression. It is commonly observed that DNA sequences with high affinity for transcription factors occur more frequently in the genome than the instances of genes bound or regulated by these factors. However, the mechanism by which transcription factors selectively identify and regulate these genes was unclear. I utilized the transcriptional control of the phosphate-responsive signaling pathway (PHO) in Saccharomyces cerevisiae as a model system to address this problem.

Organisms and their component cells exist in a dynamic and unpredictable environment. Many of these environmental changes are potentially harmful or lethal. It is therefore unsurprising that cells are capable of adaptation to many of these potentially harmful environmental conditions. This adaptation requires both the ability to gather information about the environment, and the ability to convert the information gathered into the appropriate cellular response. Cells have developed specific signal transduction pathways that respond to a specific environmental stimulus and effect a specific, corresponding cellular response. Such signal transduction pathways are quantitative, in that cells do not simply display binary information processing but are capable of more subtle interpretation of different magnitudes of a particular stimulus. In particular, many signaling pathways enable adaptation to changing levels of environmental nutrients by control of cellular gene expression. We employed the single-cell eukaryote Saccharomyces cerevisiae as a model to study several facets of nutrient-responsive signal transduction in a quantitative manner. In the following text, we present our study of the sources of heterogeneity in gene expression in a population of genetically identical cells. In addition, we review recent advances in understanding of heterogeneity or noise in gene expression. Also, we present work characterizing the zinc-responsive signaling pathway in a quantitative manner, and studies uncovering the presence of positive feedback in the phosphate-responsive (PHO) signaling pathway.

Every cell has developed mechanisms to respond to changes in its environment and to adapt its growth and metabolism to unfavorable conditions. The unicellular eukaryote yeast has long proven as a particularly useful model system for the analysis of cellular stress responses, and the completion of the yeast genome sequence has only added to its power This volume comprehensively reviews both the basic features of the yeast genral stress response and the specific adapations to different stress types (nutrient depletion, osmotic and heat shock as well as salt and oxidative stress). It includes the latest findings in the field and discusses the implications for the analysis of stress response mechanisms in higher eukaryotes as well.

The roots of most plants are colonized by symbiotic fungi to form mycorrhiza, which play a critical role in the capture of nutrients from the soil and therefore in plant nutrition. Mycorrhizal Symbiosis is recognized as the definitive work in this area. Since the last edition was published there have been major advances in the field, particularly in the area of molecular biology, and the new edition has been fully revised and updated to incorporate these exciting new developments. Over 50% new material Includes expanded color plate section Covers all aspects of mycorrhiza Presents new taxonomy Discusses the impact of proteomics and genomics on research in this area

This contributed volume reviews the recent progress in our understanding of membrane transport in yeast including both Saccharomyces cerevisiae and non-conventional yeasts. The articles provide a summary of the key transport processes and put these in a systems biology context of cellular regulation, signal reception and homeostasis. After a general introduction, readers will find review articles covering the mechanisms and regulation of transport for various substrates ranging from diverse nutrients to cations, water and protons. These articles are complemented by a chapter on extremophilic yeast, a chapter on the mathematical modelling of ion transport and two chapters on the role of transport in pathogenic yeasts and antifungal drug resistance. Each article provides both a general overview of the main transport characteristics of a specific substrate or group of substrates and the unique details that only an expert working in the field is able to transmit to the reader. Researchers and students of the topic will find this book to be a useful resource for membrane transport in yeast collecting information in one complete volume, which is otherwise scattered across many papers. This might also be interesting for scientists investigating other species in order to compare transport mechanisms with known functions in yeast with the cells on which they work.

"Methods in Yeast Genetics" is a course that has been offered annually at Cold Spring Harbor for the last 30 years. This provides a set of teaching experiments along with the protocols and recipes for the standard techniques and reagents used in the study of yeast biology.