The role of different HP1 protein complexes during the establishment of distinct chromatin structures

• Applicant: Professor Dr. Axel Imhof
• Subject Area: General Genetics and Functional Genome Biology
• Term: from 2007 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 40833040

The eukaryotic DNA is packaged into chromatin, which has a major impact on the expression of the underlying genes. The conformation of chromatin is most likely determined by the nature of the chromatin-associated factors. One of the best-studied chromatin conformations is constitutive heterochromatin, which is highly condensed and repressive in nature. One of the factors that bind specifically to heterochromatic regions is the heterochromatin binding protein HP1. Despite a wealth of genetic experiments that suggest a structural role of HP1 it is not known how HP1 leads to a repressive conformation at the molecular level. Moreover, recent experiments show that HP1 is also involved in the activation of specific genes in higher eukaryotes where additional isoforms were identified that also localise to euchromatic regions. In the proposed project we will isolate protein complexes that specifically interact with different HP1 isoforms from tissue culture cells and from embryos that express tagged isoforms in particular tissues and at certain stages of development. Based on the interacting partners that we have already identified and will identify in the future, we will analyse the function of the HP1 interacting proteins in generating specific chromatin structures. These data will then also allow us to investigate the role of individual HP1 subunits, the process of binding of HP1 isoforms to chromatin and to identify possible ways to set up such specialized chromatin structures by interfering with the interaction and/or the activities of the associated proteins.

• DFG Programme: Research Grants