Genome-wide profiling of Argonaute-chromosome interactions [ChIP-Seq]

Argonuate proteins are the central components of the RNA-induced silencing complex (RISC) which execute small RNA-mediated gene regulation mainly in the cytoplasm and their nuclear functions in mammalian cells remain largely unknown. Here we show that in human cancer cells Ago1 is pervasively associated with chromosomal loci throughout the genome with the association centered mostly on actively transcribed promoters. Ago1 but not Ago2 physically interacts with RNA polymerase II (RNAP II) in the nucleus. Moreover, genes bound by Ago1 are significantly enriched for several cancer related pathways. Detailed analysis of these genes including PIK3CA, PRKCH, CDC6 and RRM1 verified Ago1-mediated transcriptional gene regulation through Ago1-promoter interactions. We also found a strong correlation between Ago1-bound genes and genes downregulated by Ago1 depletion which, phenotypically, leads to inhibition of proliferation in different cancer cells. Therefore, our findings reveal the first landscape of human Ago1-chromosomal interactions which may drive oncogenic programs in cancer cells Examination of Ago-DNA interactions in human cancer cells