In vivo analysis of Arabidopsis HMGA and HMGB proteins

The High Mobility Group (HMG) proteins are a heterogeneous group of small and abundant non-histone proteins present in the cell nuclei of all eukaryotes. The HMG proteins were originally defined as being rich in acidic and basic amino acids, soluble in dilute acids and extractable from chromatin with0.35 M NaCl. The HMG proteins interact with the eukaryotic DNA and upon binding the proteins modulate the structure of the DNA. They thereby facilitate the binding of e.g. transcription factors to the DNA that then initiate the transcription of genes. The HMG proteins are therefore very important for the function of the organism. Although there have been reports indicating an involvement of HMG proteins in replication, transcription and nucleosome assembly, the exact cellular function of the proteins is still largely unknown. The main focus of the project is therefore to use various methods to analyse the protein functions. As a model organism, the plant is used. The study is based on three primary approaches: (1) Analyses of gene promoter activity using -promoter-reporter gene fusion, (2) examination of the developmental differences between plants lacking the HMG protein, plants having excess amount of the HMG protein and wild-type plants and (3) determination of the cellular localisation, nuclear localisation sequence and protein dynamics using HMG-GFP fusion proteins. Arabidopsis thaliana hmg hmg