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This paper presents a comprehensive set of experiments in which polaritons are excited in a semiconductor microcavity. Above a critical density of polaritons, massive occupation of the ground state at 19 K is observed and various pieces of experimental evidence point to a spontaneous onset of a macroscopic quantum phase.
Three separate labs report that p16INK4a, a protein known to be expressed in an age-dependent manner regulates ageing specifically in stem cells. Studying its role in regeneration of three different tissues, the blood, pancreas, and brain, the three groups separately found that p16INK4a is not only a biomarker, but an effector of ageing.
The crystal structures and cryo-electron microscopy reconstructions of eEF3 on its own and attached to the ribosome are resolved, providing an insight into how eEF3 functions as a translation factor on the A and E sites on a ribosome.
Sequences responsible for targeting integral membrane proteins to the inner nuclear membrane (INM) resemble classical nuclear localization signals. Recognition of these signals by the import receptor karyopherin-alpha promotes nuclear import; targeting of INM proteins is dependent on the Ran GTPase system and specific nuclear pore complex proteins.
The tumour suppressor gene PML is shown to normally restrain angiogenesis, both in tumours and under ischaemic conditions. This involves a new pathway in which during hypoxia, PML regulates mTOR and the transcription factor HIF-1α
One of the most rapidly evolving genomic regions in the human lineage corresponds to a previously unstudied RNA gene, called HAR1. Based on expression studies, it is likely that HAR1 likely plays an important role in brain biology.
In mice with the sticky mutation, the cells that are involved in motor coordination degenerate, due to a single nucleotide change in the enzyme called alanyl-tRNA synthetase. This demonstrates the potentially catastrophic consequences of small changes in the fidelity of translation.
Molecular 'snapshots' of the MnmA thiouridylase–tRNA complex reveal that during RNA sulphuration, a key α-helix forms around the active site, burying U34 into the catalytic pocket. This 'closed' conformation of the active site ensures that sulphur is incorporated into uridine at the correct place.
Examination of the viral E1 hexameric helicase structure finds that a loop of each subunit becomes attached to a nucleotide and remains associated with it during the next six steps of translocation, thereby escorting a single nucleotide through the channel.
Real food webs are structured so that top predators couple distinct energy channels that differ in both productivity and turnover rate. Theory suggests that such coupling is critical to the maintenance of food web stability, with important implications for conservation and ecosystem management.