Article
- The EMBO Journal (2007) 26, 741 - 751
- doi:10.1038/sj.emboj.7601527
Published online: 25 January 2007
Subject Categories:
HP1 controls genomic targeting of four novel heterochromatin proteins in Drosophila
Frauke Greil1,a, Elzo de Wit1, Harmen J Bussemaker2 and Bas van Steensel1
- Department of Molecular Biology, Netherlands Cancer Institute, Amsterdam, The Netherlands
- Department of Biological Sciences and Center for Computational Biology and Bioinformatics, Columbia University, New York, NY, USA
Correspondence to:
Bas van Steensel, Department of Molecular Biology, Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066 CX Amsterdam, The Netherlands. Tel.: +31 20 512 2040; Fax: +31 20 669 1383; E-mail: b.v.steensel@nki.nl
aPresent address: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
Received 12 September 2006; Accepted 23 November 2006
Abstract
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 (HPs). Three of these proteins (HP3, HP4 and HP5) interact directly with HP1, whereas 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:
- chromatin composition,
- DamID,
- position effect variegation,
- protein interactions
