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You searched for +publisher:"Penn State University" +contributor:("James E Hopper, Committee Chair/Co-Chair"). Showing records 1 – 2 of 2 total matches.

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Penn State University

1. Diep, Cuong Quoc. Analysis of the yeast Gal3 protein, a key component of the GAL gene transcription switch .

Degree: 2008, Penn State University

Transcriptional regulation of protein-encoding genes in eukaryotic organisms is required for proper development, differentiation, and response to environmental changes. The expression of specific genes at the transcriptional level is often tightly regulated to ensure that these genes are turned on or off only at the proper time and in the appropriate cell type. One of the most well studied cases of such regulation in eukaryotes is the GAL gene switch found in the yeast Saccharomyces cerevisiae. The GAL genes are necessary for the metabolism of galactose and their transcription is activated by a DNA-binding transcriptional activator, Gal4, in the presence of galactose. However, without galactose the activity of Gal4 is inhibited by its interaction with Gal80. A key regulatory component in activation of the GAL gene switch is the Gal3 protein. Gal3 senses the presence of intracellular galactose and binds to Gal80, relieving the Gal80-inhibition of Gal4. Although Gal3 interaction with Gal80 leads to Gal4-mediated activation of the GAL genes, there is a major gap of knowledge in how Gal3 itself is activated by galactose and ATP, and it is not known which amino acids of Gal3 are important for interaction with Gal80. In this thesis work, I addressed the mechanism in which Gal3 is activated by its ligands and also identified the surface and amino acids that are necessary for interaction with Gal80. Intragenic suppression analyses were performed for GAL3C mutants that confer a constitutive GAL gene activation and a galactose-independent interaction with Gal80. Of the five GAL3C alleles analyzed, four were suppressed by the second-site suppressor (GAL3SOC-D68S), while one allele (GAL3C-D368V) was not suppressed. On the Gal3 homology model, the suppressed GAL3C alleles co-localized with the second-site suppressor to the “hinge” region consisting of β-sheets s-C, -H and α-helices h-K, -O, whereas the non-suppressed allele localized to the opposite side of the “hinge” region at α-helix h-J. The GAL3C-D368V allele had previously been shown to suppress a GAL80S-G323R interaction mutation. Crosslinking results of Gal3 and Gal80 are consistent with the notion that they interact by surfaces that include Gal3-D368 and Gal80-G323. This is further supported by the localization of gal3 interaction mutants surrounding Gal3-D368 on the homology model. The data suggest that a local conformational change occurs within the “hinge” region to activate Gal3, while the interaction interface encompassing D368 plays a direct role in the binding to Gal80. Furthermore, based on considerations of E. coli galactokinase and previous attempts to isolate Gal3 interaction peptides, I conclude that the Gal80-binding surface of Gal3 is a composite of noncontiguous elements. Advisors/Committee Members: James E Hopper, Committee Chair/Co-Chair, Anita Klein Hopper, Committee Member, Sergei A Grigoryev, Committee Member, George Makhatadze, Committee Member, Vincent Chau, Committee Member.

Subjects/Keywords: GAL gene switch; transcription regulation; GAL3

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Diep, C. Q. (2008). Analysis of the yeast Gal3 protein, a key component of the GAL gene transcription switch . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7356

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Diep, Cuong Quoc. “Analysis of the yeast Gal3 protein, a key component of the GAL gene transcription switch .” 2008. Thesis, Penn State University. Accessed April 15, 2021. https://submit-etda.libraries.psu.edu/catalog/7356.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Diep, Cuong Quoc. “Analysis of the yeast Gal3 protein, a key component of the GAL gene transcription switch .” 2008. Web. 15 Apr 2021.

Vancouver:

Diep CQ. Analysis of the yeast Gal3 protein, a key component of the GAL gene transcription switch . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Apr 15]. Available from: https://submit-etda.libraries.psu.edu/catalog/7356.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Diep CQ. Analysis of the yeast Gal3 protein, a key component of the GAL gene transcription switch . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7356

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Penn State University

2. Chandy, Mark. HISTONE MODIFICATIONS INFLUENCE CHROMATIN MODIFYING AND CHROMATIN REMODELING COMPLEXES .

Degree: 2008, Penn State University

Chromatin condenses DNA and packages it into the nucleus. The fundamental unit of chromatin is the nucleosome, which compacts and forms higher order structures. Chromatin structure affects transcription, DNA replication and DNA repair. For gene expression, chromatin is dynamically modulated by chromatin modifying complexes and chromatin remodeling complexes. The histone code hypothesis predicts that modifications not only dictate the inheritance of chromatin states, but also that combinations of modifications recognized by protein-interaction domains are important for recruiting cofactors that alter chromatin structure. For over 40 years, histone acetylation has been associated with gene activation. Moreover, the discovery of histone acetyl transferase (HAT) complexes has implicated acetylation in transcription, DNA repair and even silencing. The SAGA complex is a 1.8 MDa multisubunit HAT complex that is recruited by activator at promoters. As the catalytic subunit of SAGA, Gcn5 acetylates promoter nucleosomes and produces a peaked acetylation profile upon gene induction. Moreover, the Gcn5 bromodomain is required for retention on acetylated nucleosomes. We test the importance of the Gcn5 bromodomain in restricting SAGA acetylation to the promoter using the scanning in vitro chromatin immunoprecipitation assay. The Gcn5 bromodomain does not significantly affect the nucleosomal acetylation profile of SAGA, even when the activator is removed from the array. While the Spt7 bromodomain does not retain SAGA on acetylated nucleosomes in vitro, its evolutionary conservation in yeast suggests that it may help retain SAGA on acetylated nucleosomes in vivo. When tested on phenotypic screens, the Spt7 bromodomain mutant and the Spt7 and Gcn5 double bromodomain mutant have a slight phenotype. The accumulation of acetylated histones at the promoter signals for the recruitment of other cofactors. SAGA and the ATP dependent chromatin remodeler, SWI/SNF functioned cooperatively in the activation of several genes in budding yeast. At the PHO5 promoter, both SAGA and SWI/SNF are important for timely removal of nucleosomes from the promoter. The loss of SWI/SNF results in the accumulation of H3K9 acetylated histones at this promoter, which is also an acetylation site for SAGA. Thus, SAGA acetylation at the promoter may recruit SWI/SNF and promote the displacement of acetylated nucleosomes. We directly test the influence of SAGA acetylation on SWI/SNF nucleosome displacement using several assays on the immobilized nucleosome array in vitro. SWI/SNF not only displaces acetylated nucleosomes, but it also targets promoter acetylated nucleosomes in the absence of activator. More important, SWI/SNF displacement of acetylated nucleosomes correlates with an increase in accessible DNA at the promoter. Advisors/Committee Members: James E Hopper, Committee Chair/Co-Chair, Sergei A Grigoryev, Committee Member, Michael G Fried, Committee Member, Laura Carrel, Committee Member, Jerry L Workman, Committee Chair/Co-Chair, Robert G Levenson, Committee Member.

Subjects/Keywords: SAGA; SWI/SNF; chromatin remodeling; bromodomain

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Chandy, M. (2008). HISTONE MODIFICATIONS INFLUENCE CHROMATIN MODIFYING AND CHROMATIN REMODELING COMPLEXES . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/6926

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Chandy, Mark. “HISTONE MODIFICATIONS INFLUENCE CHROMATIN MODIFYING AND CHROMATIN REMODELING COMPLEXES .” 2008. Thesis, Penn State University. Accessed April 15, 2021. https://submit-etda.libraries.psu.edu/catalog/6926.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Chandy, Mark. “HISTONE MODIFICATIONS INFLUENCE CHROMATIN MODIFYING AND CHROMATIN REMODELING COMPLEXES .” 2008. Web. 15 Apr 2021.

Vancouver:

Chandy M. HISTONE MODIFICATIONS INFLUENCE CHROMATIN MODIFYING AND CHROMATIN REMODELING COMPLEXES . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Apr 15]. Available from: https://submit-etda.libraries.psu.edu/catalog/6926.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Chandy M. HISTONE MODIFICATIONS INFLUENCE CHROMATIN MODIFYING AND CHROMATIN REMODELING COMPLEXES . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/6926

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.