Histone methyltransferase activity of a Drosophila Polycomb group repressor complex.

Polycomb group (PcG) proteins maintain transcriptional repression during development, likely by creating repressive chromatin states. The Extra Sex Combs (ESC) and Enhancer of Zeste [E(Z)] proteins are partners in an essential PcG complex, but its full composition and biochemical activities are not known. A SET domain in E(Z) suggests this ...
complex might methylate histones. We purified an ESC-E(Z) complex from Drosophila embryos and found four major subunits: ESC, E(Z), NURF-55, and the PcG repressor, SU(Z)12. A recombinant complex reconstituted from these four subunits methylates lysine-27 of histone H3. Mutations in the E(Z) SET domain disrupt methyltransferase activity in vitro and HOX gene repression in vivo. These results identify E(Z) as a PcG protein with enzymatic activity and implicate histone methylation in PcG-mediated silencing.
Mesh Terms:
Animals, Chromosomal Proteins, Non-Histone, DNA-Binding Proteins, Drosophila, Drosophila Proteins, Gene Silencing, Histone-Lysine N-Methyltransferase, Homeodomain Proteins, Insect Proteins, Lysine, Methyltransferases, Molecular Chaperones, Nuclear Proteins, Protein Methyltransferases, Recombination, Genetic, Repressor Proteins, Retinoblastoma-Binding Protein 4, Transcription Factors
Date: Oct. 18, 2002
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