Interplay Between Promoter Occupancy and Chromatin Remodeling Requirements in Transactivation of the S.cerevisiae PHO5 Gene


Book Description

In higher eukaryotes, DNA is packaged with histones and other proteins into chromatin. While this is important in the control of unwanted gene expression, chromatin also serves as a barrier to many vital functions in the cell. Therefore, cells have evolved many different types of chromatin remodeling enzymes to contend with this inhibitory structure and enable gene expression and other functions. The Saccharomyces cerevisiae PHO5 gene is triggered in response to phosphate starvation. In this study, I evaluate the chromatin remodeling requirements of this gene with respect to the multisubunit complexes SWI/SNF and SAGA. I show, for the first time, physical recruitment of SWI/SNF to the PHO5 promoter. I also demonstrate the role of promoter occupancy in influencing requirements for chromatin remodeling enzymes. Further, Idescribe various interactions between these two complexes at the PHO5 promoter. This study presents evidence for the first instance of excess recruitment of an ATP-dependent remodeler potentially compensating for the lack of a histone acetyltransferase.




Chromatin Dynamics at the Saccharomyces Cerevisiae PHO5 Promoter


Book Description

In eukaryotes, the organization of DNA into chromatin is a primary determinant of gene expression. Positioned nucleosomes in promoter regions are frequently found to regulate gene expression by obstructing the accessibility of cis-regulatory elements in DNA to trans-factors. This dissertation focuses on the chromatin structure and remodeling program at the S. cerevisiae PHO5 promoter, extending the use of DNA methyltransferases as in vivo probes of chromatin structure. Our studies address the diversity of histone-DNA interactions in vivo by examining nucleosome conformational stabilities at the PHO5 promoter. We present high-resolution chromatin structural mapping of the promoter, required to relate in vivo site accessibility to nucleosome stability and show that the PHO5 promoter nucleosomes have different accessibilities. We show a correlation between DNA curvature and nucleosome positioning, which is consistent with the observed differences in accessibility/stability. Kinetic analyses of the chromatin remodeling program at PHO5 show that nucleosomes proximal to the enhancer are disrupted preferentially and prior to those more distal, demonstrating bidirectional and finite propagation of chromatin remodeling from bound activators and providing a novel mechanism by which transactivation at a distance occurs.







Chromatin


Book Description

Chromatin: Structure, Function, and History covers the basics of chromatin biology, beginning with the discoveries that culminated in the recognition of the nucleosome as the basic subunit of chromatin. Chromatin folding, nucleosome positioning, and histone variants are discussed, as well as research on chromatin modifications and remodeling, which exploded in the early to mid-1990s and led to widespread interest in epigenetics. Considerable attention is given to methods and experiments that led to key insights and recent developments such as the use of genome-wide approaches and innovations in imaging approaches are also emphasized. By providing historical background together with detailed discussion of contemporary studies, the book aims to instill in the reader an appreciation not only of our current knowledge of chromatin structure and function, but also of the remarkable path that has taken chromatin to the forefront of modern research. Provides a current, expansive, and well-documented resource on chromatin and epigenetics Addresses the role of chromatin in transcription regulation and chromatin abnormalities in disease Reviews the historical background of specific areas of chromatin research, enabling readers to understand how the field was born and to appreciate the discoveries and technical advances that have propelled it forward




Chromatin Structure and Gene Expression


Book Description

Since publication of the first edition in 1995, there have been significant advances and understanding of chromatin structure and its relation to gene expression. These include a high-resolution structure of the nucleosome core, discovery of the enzymes and complexes that mediate histone acetylation and deacetylation, discovery of novel ATP-dependent chromatin remodeling complexes, new insights into nuclear organization and epigenetic silencing mechanisms. In light of these advances, Chromatin Structure and Gene Expression (2ed.) includes updated chapters and additional material that introduce new concepts in the process of gene regulation in chromatin.







Chromatin and Chromatin Remodeling Enzymes Part C


Book Description

DNA in the nucleus of plant and animal cells is stored in the form of chromatin. Chromatin and the chromatin remodelling enzymes play an important role in gene transcription. Genetic assays of chromatin modification and remodeling Histone modifying enzymes ATP-dependent chromatin remodeling enzymes




Handbook of Cell Signaling


Book Description

Handbook of Cell Signaling, Three-Volume Set, 2e, is a comprehensive work covering all aspects of intracellular signal processing, including extra/intracellular membrane receptors, signal transduction, gene expression/translation, and cellular/organotypic signal responses. The second edition is an up-to-date, expanded reference with each section edited by a recognized expert in the field. Tabular and well illustrated, the Handbook will serve as an in-depth reference for this complex and evolving field. Handbook of Cell Signaling, 2/e will appeal to a broad, cross-disciplinary audience interested in the structure, biochemistry, molecular biology and pathology of cellular effectors. Contains over 350 chapters of comprehensive coverage on cell signaling Includes discussion on topics from ligand/receptor interactions to organ/organism responses Provides user-friendly, well-illustrated, reputable content by experts in the field




Chromatin and Chromatin Remodeling Enzymes, Part B


Book Description

DNA in the nucleus of plant and animal cells is stored in the form of chromatin. Chromatin and the Chromatin remodelling enzymes play an important role in gene transcription.