The MES-2/MES-3/MES-6 complex and regulation of histone H3 methylation in C. elegans.
The C. elegans proteins MES-2 and MES-6, orthologs of the Polycomb group (PcG) chromatin repressors E(Z) and ESC, exist in a complex with their novel partner MES-3. The MES system participates in silencing the X chromosomes in the hermaphrodite germline. Loss of maternal MES function leads to germline degeneration and sterility. We report here that the MES complex is responsible for di- and trimethylation of histone H3 Lys27 (H3-K27) in the adult germline and in early embryos and that MES-dependent H3-K27 marks are concentrated on the X's. Another H3-K27 HMT functions in adult somatic cells, oocytes, and the PGCs of embryos. In PGCs, the MES complex may specifically convert dimethyl to trimethyl H3-K27. The HMT activity of the MES complex appears to be dependent on the SET domain of MES-2. MES-2 thus joins its orthologs Drosophila E(Z) and human EZH2 among SET domain proteins known to function as HMTs (reviewed in ). Methylation of histones is important for long-term epigenetic regulation of chromatin and plays a key role in diverse processes such as X inactivation and oncogenesis. Our results contribute to understanding the composition and roles of E(Z)/MES-2 complexes across species.
Bender
Laurel B
LB
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Cao
Ru
R
Zhang
Yi
Y
Strome
Susan
S
D000818:Animals; D015153:Blotting, Western; D017173:Caenorhabditis elegans / Q000196:embryology / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D004303:Dosage Compensation, Genetic; D005455:Fluorescent Antibody Technique; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D047468:Immunoprecipitation; D008745:Methylation; D009687:Nuclear Proteins / Q000378:metabolism*; D063146:Polycomb-Group Proteins; D011496:Protein Methyltransferases; D017434:Protein Structure, Tertiary
D029742:Caenorhabditis elegans Proteins; D006657:Histones; C098864:Mes-3 protein, C elegans; D009687:Nuclear Proteins; D063146:Polycomb-Group Proteins; C113414:mes-2 protein, C elegans; C113415:mes-6 protein, C elegans; D000076983:Histone Methyltransferases; D011496:Protein Methyltransferases; D011495:Histone-Lysine N-Methyltransferase