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dc.contributor.authorSafaee, Natasha Marieen_US
dc.date.accessioned2014-03-14T20:47:07Z
dc.date.available2014-03-14T20:47:07Z
dc.date.issued2009-08-18en_US
dc.identifier.otheretd-10282009-104413en_US
dc.identifier.urihttp://hdl.handle.net/10919/35517
dc.description.abstractEukaryotic organisms require the ability to respond to their environments. They do so by utilizing signal transduction pathways that allow for signals to effect final biological responses. Many times, these final responses require new gene expression events that have been stimulated or repressed within the nucleus. Thus, much of the understanding of signal transduction pathways converges on the understanding of how signaling affects gene expression alterations (Kumar et al., 2004). The regulation of gene expression involves the modification of chromatin between condensed (closed, silent) and expanded (open, active) states. Histone modifications, such as acetylation, can determine the open versus closed status of chromatin. The PHD (Plant HomeoDomain) finger is a structural domain primarily found in nuclear proteins across eukaryotes. This domain specifically recognizes the epigenetic marks H3K4me2 and H3K4me3, which are di- and tri-methylated lysine 4 residues of Histone H3 (Loewith et al., 2000; Kuzmichev et al., 2002; Vieyra et al. 2002; Shiseki et al., 2003; Pedeux et al., 2005, Doyon et al., 2006). It is estimated that there are ~150 proteins that contain the PHD finger in humans (Solimon and Riabowol, 2007). The PHD finger is conserved in yeast and plants, however an analysis of this domain has only been performed done in Arabidopsis thaliana (Lee et al., 2009). The work presented in this report aims to extend the analysis of this domain in plants by identifying the PHD fingers of the crop species Oryza sativa (rice). In addition, a phylogenetic analysis of all PHD fingers in Arabidopsis and rice was undertaken. From these analyses, it was determined that there are 78 PHD fingers in Arabidopsis and 70 in rice. In addition, these domains can be categorized into classes and groups by defining features within the conserved motif. In a separate study, I investigated the function of two of the PHD finger proteins from Arabidopsis, ING1 (INhibitor of Growth1) and ING2. In humans, these proteins can be found in complexes associated with both open and closed chromatin. They facilitate chromatin remodeling by recruiting histone acetyltransferases and histone deacetylases to chromatin (Doyon et al., 2006, Pena et al., 2006). In addition, these proteins recognize H3K4me2/3 marks and are believed to be â interpretersâ of the histone code (Pena et al., 2006, Shi et al., 2006). To understand the function of ING proteins in plants, I took a reverse genetics approach and characterized ing1 and ing2 mutants. My analysis revealed that these mutants are altered in time of flowering, as well as their response to nutrient and stress conditions. Lastly, I was able to show that ING2 protein interacts in vitro with SnRK1.1, a nutrient/stress sensor (Baena-Gonzalez et al., 2007). These results indicate a novel function for PHD proteins in plant growth, development and stress response.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartSafaee_NM_T_2009.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectInhibitor of Growthen_US
dc.subjectH3K4me3en_US
dc.subjectArabidopsis thalianaen_US
dc.subjectOryza sativaen_US
dc.subjectchromatin remodelingen_US
dc.subjectPlant Homeodomainen_US
dc.titleAnalysis of Plant Homeodomain Proteins and the Inhibitor of Growth Family Proteins in Arabidopsis thalianaen_US
dc.typeThesisen_US
dc.contributor.departmentBiochemistryen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineBiochemistryen_US
dc.contributor.committeechairGillaspy, Glenda E.en_US
dc.contributor.committeememberTokuhisa, Jamesen_US
dc.contributor.committeememberMahaney, Jamesen_US
dc.contributor.committeememberDolan, Erinen_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10282009-104413/en_US
dc.date.sdate2009-10-28en_US
dc.date.rdate2013-05-21
dc.date.adate2010-01-04en_US


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