Regulation of Id2 expression by CCAAT/enhancer binding protein β

Mice deficient for Id2, a negative regulator of basic helix–loop–helix (bHLH) transcription factors, exhibit a defect in lactation due to impaired lobuloalveolar development during pregnancy, similar to the mice lacking the CCAAT enhancer binding protein (C/EBP) β. Here, we show that Id2 is a direct target of C/EBPβ. Translocation of C/EBPβ into the nucleus, which was achieved by using a system utilizing the fusion protein between C/EBPβ and the ligand-binding domain of the human estrogen receptor (C/EBPβ-ERT), demonstrated the rapid induction of endogenous Id2 expression. In reporter assays, transactivation of the Id2 promoter by C/EBPβ was observed and, among three potential C/EBPβ binding sites found in the 2.3 kb Id2 promoter region, the most proximal element was responsible for the transactivation. Electrophoretic mobility shift assay (EMSA) identified this element as a core sequence to which C/EBPβ binds. Chromatin immunoprecipitation (ChIP) furthermore confirmed the presence of C/EBPβ in the Id2 promoter region. Northern blotting showed that Id2 expression in C/EBPβ-deficient mammary glands was reduced at 10 days post coitus (d.p.c.), compared with that in wild-type mammary glands. Thus, our data demonstrate that Id2 is a direct target of C/EBPβ and provide insight into molecular mechanisms underlying mammary gland development during pregnancy

Role of the Carboxy-Terminal Region of the GluRε2 Subunit in Synaptic Localization of the NMDA Receptor Channel

AbstractThe synaptic localization of the N-methyl-D-aspartate (NMDA) type glutamate receptor (GluR) channel is a prerequisite for synaptic plasticity in the brain. We generated mutant mice carrying the carboxy-terminal truncated GluRε2 subunit of the NMDA receptor channel. The mutant mice died neonatally and failed to form barrelette structures in the brainstem. The mutation greatly decreased the NMDA receptor–mediated component of hippocampal excitatory postsynaptic potentials and punctate immunofluorescent labelings of GluRε2 protein in the neuropil regions, while GluRε2 protein expression was comparable. Immunostaining of cultured cerebral neurons showed the reduced punctate staining of the truncated GluRε2 protein at synapses. These results suggest that the carboxy-terminal region of the GluRε2 subunit is important for efficient clustering and synaptic localization of the NMDA receptor channel

Ocular dominance affects magnitude of dipole moment: An MEG study

横浜栄共済病院脳卒中診療科・脳神経外科To investigate whether the ocular dominance affects laterality in the activity of the primary visual cortex, we examined the relationship between the ocular dominance and latency or dipole moment measured by checkerboard-pattern and magnetoencephalography in 11 right-handed healthy male participants. Participants with left-eye dominance showed a dipole moment of 21.5±6.1 nAm with left-eye stimulation and 16.1±3.6 nAm with right, whereas those with right-eye dominance showed a dipole moment of 18.0±5.2 and 21.5±2.7 nAm with left-eye and right-eye stimulation of the infero-medial quadrant visual field, respectively. Thus, the dipole moment was higher when the dominant eye was stimulated, which implies that ocular dominance is regulated by the ipsilateral occipital lobe. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins

Mechanism of the performance improvement of TiO2-x-based field-effect transistor using SiO2 as gate insulator

RF magnetron sputtered titanium oxide (TiO2-x) thin films were used as active channel layer to fabricate field-effect transistors (FETs). In the as-prepared FETs, poor FET performance was found, with a low on-to-off current ratio of ∼500 and a high sub-threshold slope. It is attributed the existence of Si-O-Ti cross-linking bonding at TiO2-x/SiO2 interface, which was probed by X-ray Photoelectron Spectroscopy (XPS) measurement. A remark improvement of sub-threshold slope and on-to-off current ratio was observed due to post annealing in vacuum at 300 °C for 30min. By using the electron energy loss spectroscope (EELS) analysis, oxidization of TiO2-x layer closing to SiO2 layer region was found, suggesting that Si-O-Ti cross-linking bonding at TiO2-x/SiO2 interface breaks due to post annealing treatment