In Cell Metabolism this week, Francis Collins and his colleagues at the National Human Genome Research Institute provide a "global snapshot of the human islet epigenome," with which they've elucidated insights into type 2 diabetes susceptibility loci. By performing a genome-wide analysis of sites hypersensitive to DNAse I, the NHGRI-led team found around 18,000 putative promoters, several hundred of which were previously "unannotated and islet-active," the authors write. Of more than 34,000 distal promoter elements, the team found that 47 percent are islet unique. Further, of 18 T2D loci they examined, Collins et al. discovered "118 putative regulatory elements and confirmed enhancer activity for 12 of 33 tested."
In a paper published online in advance in Cell this week, the Stanford University School of Medicine's Michael Snyder and his colleagues describe "extensive in vivo metabolite-protein interactions," between ergosterol biosynthetic proteins, protein kinases, and small metabolites, which they deduced using a custom mass spec-based assay. Snyder et al. show that ergosterol biosynthetic proteins may serve as a general regulator. In addition, the Stanford team identifies "potential key regulatory steps in lipid biosynthetic pathways, and suggests that small metabolites may play a more general role as regulators of protein activity and function than previously appreciated."
Columbia University's J. Robert Hogg and Stephen Goff show in this week's Cell that "Upf1 senses 3'[untranslated region] length to potentiate mRNA decay." More specifically, by purifying messenger ribonucleoproteins assembled on transcripts with HIV-1 3' sequences using RNA hairpin-tagged mRNAs, the team found that the Upf1-dependent degradation of mRNAs occurs through a two-step mechanism. Further, Hogg and Goff show that "by modulating the efficiency of translation termination, recognition of long 3'UTRs by Upf1 is uncoupled from the initiation of decay."
In another Cell paper published this week, and international research team shows that the "ATR-X syndrome protein targets tandem repeats" in both telomeres and euchromatic, and "influences allele-specific expression in a size-dependent manner," which could explain, in part, "the variable phenotypes seen with identical ATRX mutations." In addition, because they found that ATRX binds G-quadruplex structures in their in vitro analyses, the researchers suggest that "ATRX may play a role in various nuclear processes."