BIOL 483 Lecture Notes - Lecture 69: Stem Cell, Prc2, X-Inactivation
Document Summary
Function of h3k27me3: recruits silencing facotrs (eg. canonical prc1, prevents h3k27ac through mutual exclusion, altered nucleosome packaging, indirectly creating impediments for transcription, inheritance/ memory of silent state - propagated to inherit/ remember silent state of gene locus. Unclear whether polycomb establishment (h3k27me3) or silencing came first. H3k27me3 comes about by prc2 catalysing the methylation of h3k27 to repress transcription at gene loci. Prc2 biological roles: x inactivation, imprinting, stem cell maintenance, differentiation. Ezh2 - prc2 subunit that acts as marker for tumour metastasis. > set domain responsible for methyhaltion activity of complex. 2 model organism yeasts don"t have any prc2. Contains additional accessory proteins to modulate activity of prc2. > eg. if epop and pcl associate with prc2 then cannot have aebp2 and. Aromatic cage fits h3k27me3 to induce confomrational change that poises catalytic domain of ezh2 to methylate target peptides.
