653 research outputs found
The APC/C Coordinates Retinal Differentiation with G1 Arrest through the Nek2-Dependent Modulation of Wingless Signaling
The cell cycle is coordinated with differentiation during animal development. Here we report a cell-cycle-independent developmental role for a master cell-cycle regulator, the anaphase-promoting complex or cyclosome (APC/C), in the regulation of cell fate through modulation of Wingless (Wg) signaling. The APC/C controls both cell-cycle progression and postmitotic processes through ubiquitin-dependent proteolysis. Through an RNAi screen in the developing eye, we found that partial APC/C inactivation severely inhibits retinal differentiation independently of cell-cycle defects. The differentiation inhibition coincides with hyperactivation of Wg signaling caused by the accumulation of a Wg modulator, Nek2 (dNek2). The APC/C degrades dNek2 upon synchronous G1 arrest prior to differentiation, which allows retinal differentiation through local suppression of Wg signaling. We also provide evidence that decapentaplegic signaling may posttranslationally regulate this APC/C function. Thus, the APC/C coordinates cell-fate determination with the cell cycle through the modulation of developmental signaling pathways.T.M. and F.M. were partly supported by a CRUK Fellowship to Y.K. T.M. thanks the European Commission for a Marie Curie fellowship
Anomalous vortex dynamics in spin-triplet superconductor UTe
The vortex dynamics in the spin-triplet superconductor, UTe, are studied
by measuring the DC electrical resistivity with currents along the -axis
under magnetic fields along the -axis. Surprisingly, we have discovered an
island region of low critical current deep inside the superconducting (SC)
state, well below the SC upper critical field, attributed to a weakening of
vortex pinning. Notably, this region coincides with the recently proposed
intermediate-field SC state. We discuss the possibility of nonsingular vortices
in the intermediate state, where SC order parameter does not vanish entirely in
the vortex cores due to the mixing of multiple SC components
Detection of the interfacial exchange field at a ferromagnetic insulator-nonmagnetic metal interface with pure spin currents
At the interface between a nonmagnetic metal (NM) and a ferromagnetic
insulator (FI) spin current can interact with the magnetization, leading to a
modulation of the spin current. The interfacial exchange field at these FI-NM
interfaces can be probed by placing the interface in contact with the spin
transport channel of a lateral spin valve (LSV) device and observing additional
spin relaxation processes. We study interfacial exchange field in lateral spin
valve devices where Cu spin transport channel is in proximity with
ferromagnetic insulator EuS (EuS-LSV) and yttrium iron garnet
YFeO (YIG-LSV). The spin signals were compared with reference
lateral spin valve devices fabricated on nonmagnetic Si/SiO substrate with
MgO or AlO capping. The nonlocal spin valve signal is about 4 and 6 times
lower in the EuS-LSV and YIG-LSV, respectively. The suppression in the spin
signal has been attributed to enhanced surface spin-flip probability at the
Cu-EuS (or Cu-YIG) interface due to interfacial spin-orbit field. Besides spin
signal suppression we also found widely observed low temperature peak in the
spin signal at 30 K is shifted to higher temperature in the case of
devices in contact with EuS or YIG. Temperature dependence of spin signal for
different injector-detector distances reveal fluctuating exchange field at
these interfaces cause additional spin decoherence which limit spin relaxation
time in addition to conventional sources of spin relaxation. Our results show
that temperature dependent measurement with pure spin current can be used to
probe interfacial exchange field at the ferromagnetic insulator-nonmagnetic
metal interface.Comment: 10 pages, 3 figures, accepted in Physical Review
Quasi-Two-Dimensional Fermi Surfaces and Coherent Interlayer Transport in KFeAs
We report the results of the angular-dependent magnetoresistance oscillations
(AMROs), which can determine the shape of bulk Fermi surfaces in
quasi-two-dimensional (Q2D) systems, in a highly hole-doped Fe-based
superconductor KFeAs with 3.7 K. From the AMROs, we
determined the two Q2D FSs with rounded-square cross sections, corresponding to
12% and 17% of the first Brillouin zone. The rounded-squared shape of the FS
cross section is also confirmed by the analyses of the interlayer transport
under in-plane fields. From the obtained FS shape, we infer the character of
the 3d orbitals that contribute to the FSs.Comment: 4 pages, 4 figures, accepted in Phys. Rev. Let
Quantum oscillations in a centrosymmetric skyrmion-hosting magnet GdRu2Si2
We have performed magnetic torque and resistivity measurements on a
centrosymmetric skyrmion-host GdRu2Si2, in which the dominant magnetic
interaction leading to skyrmion formation is under debate. We observe both the
de Haas-van Alphen and Shubnikov-de Haas oscillations in the forced
ferromagnetic phase. The angular dependence of the quantum oscillation
frequencies can be reproduced by the ab-initio calculation. The de Haas-van
Alphen oscillation is also observed in the double-Q phase with a different
frequency to that in the forced ferromagnetic phase, indicating a Fermi surface
reconstruction due to the coupling between localized spins and conduction
electrons. Based on these experimental findings, the magnetic interactions in
this system are discussed.Comment: 11 pages, 8 figure
Arabidopsis IRE1 catalyses unconventional splicing of bZIP60 mRNA to produce the active transcription factor
IRE1 plays an essential role in the endoplasmic reticulum (ER) stress response in yeast and mammals. We found that a double mutant of Arabidopsis IRE1A and IRE1B (ire1a/ire1b) is more sensitive to the ER stress inducer tunicamycin than the wild-type. Transcriptome analysis revealed that genes whose induction was reduced in ire1a/ire1b largely overlapped those in the bzip60 mutant. We observed that the active form of bZIP60 protein detected in the wild-type was missing in ire1a/ire1b. We further demonstrated that bZIP60 mRNA is spliced by ER stress, removing 23 ribonucleotides and therefore causing a frameshift that replaces the C-terminal region of bZIP60 including the transmembrane domain (TMD) with a shorter region without a TMD. This splicing was detected in ire1a and ire1b single mutants, but not in the ire1a/ire1b double mutant. We conclude that IRE1A and IRE1B catalyse unconventional splicing of bZIP60 mRNA to produce the active transcription factor
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