A Complex with Chromatin Modifiers That Occupies E2F- and Myc-Responsive Genes in G ₀ Cells

Abstract

E2F-6 contributes to gene silencing in a manner independent of retinoblastoma protein family members. To better elucidate the molecular mechanism of repression by E2F-6, we have purified the factor from cultured cells. E2F-6 is found in a multimeric protein complex that contains Mga and Max, and thus the complex can bind not only to the E2F-binding site but also to Myc- and Brachyury-binding sites. Moreover, the complex contains chromatin modifiers such as a novel histone methyltransferase that modifies lysine 9 of histone H3, HP1gamma, and Polycomb group (PcG) proteins. The E2F-6 complex preferentially occupies target promoters in G0 cells rather than in G1 cells. These data suggest that these chromatin modifiers contribute to silencing of E2F- and Myc-responsive genes in quiescent cells.

Gradual development of a genome‐wide H3‐K9 trimethylation pattern in paternally derived pig pronucleus

“…The species difference in development of the paternal H3-K9 methylation pattern might simply be due to the activity of certain histone methyltransferases (HMTases) in the oocyte cytoplasm. Various H3-K9-specific HMTases have been characterized to date, including SUVAR39 (Rea et al, 2000;Nakayama et al, 2001), G9A (Tachibana et al, 2002), GLP/ Eu-HMTase (Ogawa et al, 2002), SETDB1 (Schultz et al, 2002;Yang et al, 2002;Dodge et al, 2004), and SETDB2 (Mabuchi et al, 2001). Currently, however, it is unknown which activity, or combination of activities, is responsible for development of the paternal H3-m 3 K9 pattern in the pig and whether the activity responsible is absent from, or inhibited in, the mouse fertilized oocyte.…”

Roles of jumonji and jumonji family genes in chromatin regulation and development

“…Several large protein complexes would have multiple or sequential functions (Ogawa et al, 2002), similar to that of "a factory." It is possible that jumonji family proteins are one of the members in the "factory."…”

E2F6 negatively regulates ultraviolet-induced apoptosis via modulation of BRCA1

“…12 Overexpression of E2F6 leads to accumulation of cells in the S-phase and delays re-entry into the cell cycle in quiescent cells. 13 More recently, E2F6 has been suggested to repress transcription of BRCA1, CTIP, ART27, HP-1a, and RBAP48 genes (which encode functions involved in tumor suppression and maintenance of chromatin structure) via its repression of the target promoter. 14 However, the biological function of E2F6 is not fully understood.…”