Histone modifications and the Arabidopsis thaliana circadian clock

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dc.contributor.advisorRoden, Lauraen_ZA
dc.contributor.authorMotleleng, Liabo Lilianen_ZA
dc.date.accessioned2015-11-08T04:59:07Z
dc.date.available2015-11-08T04:59:07Z
dc.date.issued2010en_ZA
dc.descriptionIncludes bibliographical references (leaves 61-84).en_ZA
dc.description.abstractThe circadian system has a regulatory role in almost all aspects of a plant's life. In Arabidopsis thaliana, almost 36% of the genome has been shown to be circadianly regulated and many genes that are circadianly regulated have been shown to be light responsive or involved in light responses. Rhythmic histone acetylation has been demonstrated in the promoter of TIMING OF CAB EXPRESSION1 (TOC1). Here, I used semi-quantitative Reverse Transcriptase Polymerase Chain Reaction (semi-quantitative RT -PCR) to investigate which enzymes are involved in the rhythmic expression of TOC1. I also determined whether loss-of-function histone acetylation and methylation mutants could affect the overall functioning of the circadian oscillator by measuring their circadian leaf movement and delayed fluorescence (DF) rhythms. GCN5/ HAG1 mutant plants (gcn5) exhibited erratic TOC1 expression in both constant dark (DD) and constant light (LL) conditions. Although TOC1 expression appeared to be rhythmic in both DD and LL conditions, the waveform of the rhythm was altered in TATA-binding protein associated factor 1 (taf1) mutants. This suggested that TAF1 and GCN5 might play different roles in the rhythmic histone acetylation affecting TOC1 expression. DF data and leaf movement data indicated that both TAF1 and GCN5 might play a role in the overall functioning of the A. thaliana circadian clock. Arrhythmic TOC1 expression and DF was observed in histone deacetylase 1 (hd1) mutants, suggesting that HD1 is not only involved in the rhythmic histone deacetylation affecting TOC1 expression but in the overall functioning of the circadian clock. Semi-quantitative RTPCR, DF and leaf movement studies demonstrated that CURLY LEAF (CLF), a histone methylase is involved in both the histone methylation affecting TOC1 expression and in the overall functioning of the A. thaliana circadian clock.en_ZA
dc.identifier.apacitationMotleleng, L. L. (2010). <i>Histone modifications and the Arabidopsis thaliana circadian clock</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology. Retrieved from http://hdl.handle.net/11427/14719en_ZA
dc.identifier.chicagocitationMotleleng, Liabo Lilian. <i>"Histone modifications and the Arabidopsis thaliana circadian clock."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 2010. http://hdl.handle.net/11427/14719en_ZA
dc.identifier.citationMotleleng, L. 2010. Histone modifications and the Arabidopsis thaliana circadian clock. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Motleleng, Liabo Lilian AB - The circadian system has a regulatory role in almost all aspects of a plant's life. In Arabidopsis thaliana, almost 36% of the genome has been shown to be circadianly regulated and many genes that are circadianly regulated have been shown to be light responsive or involved in light responses. Rhythmic histone acetylation has been demonstrated in the promoter of TIMING OF CAB EXPRESSION1 (TOC1). Here, I used semi-quantitative Reverse Transcriptase Polymerase Chain Reaction (semi-quantitative RT -PCR) to investigate which enzymes are involved in the rhythmic expression of TOC1. I also determined whether loss-of-function histone acetylation and methylation mutants could affect the overall functioning of the circadian oscillator by measuring their circadian leaf movement and delayed fluorescence (DF) rhythms. GCN5/ HAG1 mutant plants (gcn5) exhibited erratic TOC1 expression in both constant dark (DD) and constant light (LL) conditions. Although TOC1 expression appeared to be rhythmic in both DD and LL conditions, the waveform of the rhythm was altered in TATA-binding protein associated factor 1 (taf1) mutants. This suggested that TAF1 and GCN5 might play different roles in the rhythmic histone acetylation affecting TOC1 expression. DF data and leaf movement data indicated that both TAF1 and GCN5 might play a role in the overall functioning of the A. thaliana circadian clock. Arrhythmic TOC1 expression and DF was observed in histone deacetylase 1 (hd1) mutants, suggesting that HD1 is not only involved in the rhythmic histone deacetylation affecting TOC1 expression but in the overall functioning of the circadian clock. Semi-quantitative RTPCR, DF and leaf movement studies demonstrated that CURLY LEAF (CLF), a histone methylase is involved in both the histone methylation affecting TOC1 expression and in the overall functioning of the A. thaliana circadian clock. DA - 2010 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2010 T1 - Histone modifications and the Arabidopsis thaliana circadian clock TI - Histone modifications and the Arabidopsis thaliana circadian clock UR - http://hdl.handle.net/11427/14719 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/14719
dc.identifier.vancouvercitationMotleleng LL. Histone modifications and the Arabidopsis thaliana circadian clock. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Molecular and Cell Biology, 2010 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/14719en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Molecular and Cell Biologyen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMolecular and Cell Biologyen_ZA
dc.titleHistone modifications and the Arabidopsis thaliana circadian clocken_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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