Originally published as Genetics Published Articles Ahead of Print on July 2, 2006.

Genetics, Vol. 174, 241-251, September 2006, Copyright © 2006
doi:10.1534/genetics.106.059980

Drosophila Reptin and Other TIP60 Complex Components Promote Generation of Silent Chromatin

Dai Qi, Haining Jin1, Tobias Lilja and Mattias Mannervik2

Department of Developmental Biology, Wenner-Gren Institute, Arrhenius Laboratories E3, Stockholm University, S-106 91 Stockholm, Sweden

2 Corresponding author: Department of Developmental Biology, Wenner-Gren Institute, Arrhenius Laboratories E3, Stockholm University, S-106 91 Stockholm, Sweden.
E-mail: mannervik{at}devbio.su.se

Histone acetyltransferase (HAT) complexes have been linked to activation of transcription. Reptin is a subunit of different chromatin-remodeling complexes, including the TIP60 HAT complex. In Drosophila, Reptin also copurifies with the Polycomb group (PcG) complex PRC1, which maintains genes in a transcriptionally silent state. We demonstrate genetic interactions between reptin mutant flies and PcG mutants, resulting in misexpression of the homeotic gene Scr. Genetic interactions are not restricted to PRC1 components, but are also observed with another PcG gene. In reptin homozygous mutant cells, a Polycomb response-element-linked reporter gene is derepressed, whereas endogenous homeotic gene expression is not. Furthermore, reptin mutants suppress position-effect variegation (PEV), a phenomenon resulting from spreading of heterochromatin. These features are shared with three other components of TIP60 complexes, namely Enhancer of Polycomb, Domino, and dMRG15. We conclude that Drosophila Reptin participates in epigenetic processes leading to a repressive chromatin state as part of the fly TIP60 HAT complex rather than through the PRC1 complex. This shows that the TIP60 complex can promote the generation of silent chromatin.


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Genetics 2006 174: NP. [Full Text]