Rockefeller University's Ronen Sadeh and C. David Allis discuss in the current issue of Cell the relevance of recent studies that have mapped nucelosomes across the yeast and human genomes. Sadeh and Allis say that data from these studies suggest two models of nucleosome organization: "Chromatin remodelers position nucleosomes around transcriptional start sites in yeast, and a few locked nucleosomes may serve as barriers from which nucleosome arrays emanate in human genomes."
Elsewhere in the issue, Columbia University's Andrea Califano and his colleagues report on an miRNA-mediated network of RNA-RNA interactions, which they say "regulates established oncogenic pathways in gliblastoma." By analyzing gene expression and miRNA profile data for glioblastoma, the team uncovered evidence that "miR-mediated interactions provide a mechanistic, experimentally validated rationale for the loss of PTEN expression in a large number of glioma samples with an intact PTEN locus."
Over in Molecular Cell, researchers at the Stanford University School of Medicine discuss principles of RNA-chromatin interactions derived from genome-wide maps of lncRNA occupancy that they generated using ChIRP-seq — chromatin isolation by RNA purification followed by deep sequencing. "ChIRP-seq of three lncRNAs reveal that RNA occupancy sites in the genome are focal, sequence-specific, and numerous" in Drosophila, the authors write.