Celsr1 coordinates the planar polarity of vestibular hair cells during inner ear development.

Vestibular hair cells of the inner ear are specialized receptors that detect mechanical stimuli from gravity and motion via the deflection of a polarized bundle of stereocilia located on their apical cell surfaces. The orientation of stereociliary bundles is coordinated between neighboring cells by core PCP proteins including the large adhesive G-protein coupled receptor Celsr1. We show that mice lacking Celsr1 have vestibular behavioral phenotypes including circling. In addition, we show that Celsr1 is asymmetrically distributed at cell boundaries between hair cells and neighboring supporting cells in the developing vestibular and auditory sensory epithelia. In the absence of Celsr1 the stereociliary bundles of vestibular hair cells are misoriented relative to their neighbors, a phenotype that is greatest in the cristae of the semicircular canals. Since horizontal semi-circular canal defects lead to circling in other mutant mouse lines, we propose that this PCP phenotype is the cellular basis of the circling behavior in Celsr1 mutants

Oligomeric ferrocene rings

Cyclic oligomers comprising strongly interacting redox-active monomer units represent an unknown, yet highly desirable class of nanoscale materials. Here we describe the synthesis and properties of the first family of molecules belonging to this compound category—differently sized rings comprising only 1,1′-disubstituted ferrocene units (cyclo[n], n = 5–7, 9). Due to the close proximity and connectivity of centres (covalent Cp–Cp linkages; Cp = cyclopentadienyl) solution voltammograms exhibit well-resolved, separated 1e– waves. Theoretical interrogations into correlations based on ring size and charge state are facilitated using values of the equilibrium potentials of these transitions, as well as their relative spacing. As the interaction free energies between the redox centres scale linearly with overall ring charge and in conjunction with fast intramolecular electron transfer (∼107 s−1), these molecules can be considered as uniformly charged nanorings (diameter ∼1–2 nm)