In many systems, RNAi-related mechanisms can initiate the targeting of repressive chromatin machinery to genomic loci, and subsequent maintenance activities enforce heritable repression [ 77].
But journalists also are increasingly targets of repressive governments — in Russia, Mexico, the Philippines and now in the Middle East.
It is known that the apterous locus is a target of the repressive Polycomb Group (PcG) system.
Our findings suggested the most important cue for cis-acting lncRNA might be transcription through a particular region (e.g., cis-regulating elements, such as promoter, silencer and insulator) via specific interaction with chromatin to mediate targeted recruitment of repressive epigenetic-modifying activities to silence transcription.
Wang, X. et al. Targeting of polycomb repressive complex 2 to RNA by short repeats of consecutive guanines.
Enforced expression of HOTAIR in epithelial cancer cells induced genome-wide re-targeting of Polycomb repressive complex 2 (PRC2) to an occupancy pattern more resembling embryonic fibroblasts, leading to altered histone H3 lysine 27 methylation, gene expression, and increased cancer invasiveness and metastasis in a manner dependent on PRC2.
Here, we focus on recent evidence that links DNA methylation to the genomic targeting of Polycomb repressive complexes (PRCs), the effectors of the Polycomb system.
Further, their studies provide a molecular hint on the direct or indirect target of Pgc's repressive action.
H3K27 is an important target of PRC2 (Polycomb repressive complex 2) complexes that contain EZH2 or EZH1 histone methyl transferases.
Mapping of the targets of PcG-repressive protein complex (PRC 1 and PRC2 in mouse and human ES cells by ChIP-chip showed that PRC proteins occupy many common repressed target genes, including lineage-specific transcription factors [ 37, 38].
