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The Roles of HMGA Proteins Essay

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Despite a wealth of biochemical in vitro data on the HMGA proteins of various organisms, their biological role in chromatin is still not convincingly clarified. Current evidence suggests that HMG proteins serve a global role in chromatin by conferring a more “open” configuration to chromatin regions that are more accessible to transcriptional regulators (Bianchi and Agresti, 2005; Catez et al., 2004). In addition, there is massive evidence that HMGA proteins act as architectural factors that facilitate assembly of functional transcription factor complexes (enhanceosomes) at DNA target sites by various mechanisms. Several studies analysing altered expression levels of HMGA genes in animals have demonstrated that the chromosomal HMGA…show more content…
Therefore, it is the overall aim of my PhD project to gain insight into the in planta functions of HMGA proteins. The project will be performed in the laboratory of Prof. Dr. K.D. Grasser (Regensburg University), whose research group is specialised on studying plant chromosomal proteins. Towards the goal of elucidating HMGA function, a variety of experimental approaches will be employed using as central tool Arabidopsis plants with altered levels of HMGA protein that will be analysed in comparison to wild type control plants. The available data suggest that HMGA proteins as cofactors assist the proper transcription of putative target genes (Grasser, 2003; Klosterman and Hadwiger, 2002). To evaluate this assumption, (1) we intend to examine plants that have reduced amounts of HMGA (T-DNA insertion mutants, amiRNA plants) as well as plants that have elevated levels of HMGA (overexpression plants). Using these plants we will analyse (2) the consequences of altered HMGA levels on plant phenotype and transcriptome. In addition, (3) the spatial and temporal expression pattern of HMGA is examined as well as (4) protein interactions of HMGA.

3. Work program and Methodology
WP1. Starting point of the project is the molecular analysis of Arabidopsis candidate DNA insertion lines (obtained from the NASC stock center) harbouring T-DNA insertions in the gene encoding HMGA. Typically seeds of a segregating population are
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