Project description:The family of Heterochromatin Protein 1 (HP1) consists of highly conserved proteins, which have important functions in the nucleus of eukaryotic cells. In mammals there are three HP1 paralogs: HP1(alpha), Hp1(beta), and Hp1(gamma)They are encoded by the Cbx5, Cbx1, and Cbx3 genes, respectively. Hp1 and Hp1 stably interact with Chd4 and Adnp to form the ChAHP complex. In this project, Chd4, Adnp, and the three Cbx genes were endogenously tagged with a FLAG-Avi tag in mouse embryonic stem cells. The tagged proteins were subjected to tandem-affinity purification and analysis by mass spectrometry.
Project description:The transcriptome of Leptosphaeria maculans was analysed in mycelium of the wild type isolate v23.1.3 or in transformants silenced for DIM5 or HP1, two genes encoding enzymes involved in chromatin remodelling. The array probes were designed from gene models from the L. maculans whole genome annotation. The aim of this study was to characterise the effect of chromatin remodelling on gene expression during in vitro growth. We performed 9 hybridizations (NimbleGen) with samples derived from mycelium of a wild type isolate, v23.1.3, of a transformant silenced for HP1 and for a transformant silenced for DIM5. Three replicates each. All samples were labeled with Cy3.
Project description:Heterochromatin is important for the maintenance of genome stability and regulation of gene expression, yet our knowledge of heterochromatin structure and function is incomplete. We identified four novel Drosophila heterochromatin proteins. Three of these proteins (HP3, HP4, and HP5) interact directly with HP1, while HP6 in turn binds to each of these three proteins. Immunofluorescence microscopy and genome-wide mapping of in vivo binding sites shows that all four proteins are components of heterochromatin. Depletion of HP1 causes redistribution of all four proteins, indicating that HP1 is essential for their heterochromatic targeting. Finally, mutants of HP4 and HP5 are dominant suppressors of position effect variegation, demonstrating their importance in heterochromatic gene silencing. These results indicate that HP1 acts as a docking platform for several mediator proteins that contribute to heterochromatin function. Keywords: DamID knock-down
