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N Miki

Publications and source records attributed to N Miki.

At least 37 records · Page 2Linked to original sources
PubMed1999

Arcadlin is a neural activity-regulated cadherin involved in long term potentiation.

Neural activity results in long term changes that underlie synaptic plasticity. To examine the molecular basis of activity-dependent plasticity, we have used differential cloning techniques to identify genes that are rapidly induced in brain neurons by synaptic activity. Here, we identify a novel cadherin molecule Arcadlin (activity-regulated cadherin-like protein). arcadlin mRNA is rapidly and transiently induced in hippocampal granule cells by seizures and by N-methyl-D-aspartate-dependent synaptic activity in long term potentiation. The extracellular domain of Arcadlin is most homologous to protocadherin-8; however, the cytoplasmic region is distinct from that of any cadherin family member. Arcadlin protein is expressed at the synapses and shows a homophilic binding activity in a Ca2+-dependent manner. Furthermore, application of Arcadlin antibody reduces excitatory postsynaptic potential amplitude and blocks long term potentiation in hippocampal slices. Its close homology with cadherins, its rapid inducibility by neural activity, and its involvement in synaptic transmission suggest that Arcadlin may play an important role in activity-induced synaptic reorganization underlying long term memory.

Amino Acid Sequence↗
PubMed1999

Expression of gicerin, a cell adhesion molecule, in the abnormal retina in silver plumage color mutation of Japanese quail (Coturnix japonica).

Silver plumage color mutant (B/B) quail has an abnormal retina characterizing the transdifferentiation of retinal pigment epithelium (RPE) following the retinal separation in the early developmental stage. In the present study; (i) the expression of gicerin, an immunoglobulin-superfamily cell adhesion molecule, was examined in the retina of B/B quail. In the wild-type quail, gicerin protein was enriched in the apical membrane (facing the neural retina, NR) of RPE cells on embryonic day (E) 4 and then appeared also in NR cells from E5. However, in the B/B retina, no gicerin expression was found in the transdifferentiation area of RPE prior to the retinal separation. (ii) In addition to this, microinjection of anti-gicerin polyclonal antibody into the eyeball of wild-type quail on E3 caused the retinal separation and induced the transdifferentiation of RPE into new NR. These observations suggest that the decrease of gicerin expression might participate in the retinal separation and RPE-transdifferentiation in B/B quail.

Animals↗
PubMed1999

Involvement of gicerin, a cell adhesion molecule, in development and regeneration of oviduct and metastasis of oviductal adenocarcinomas of the chicken.

Gicerin is a novel cell adhesion molecule in the immunoglobulin superfamily and has both homophilic adhesion and heterophilic adhesive activity to neurite outgrowth factor (NOF), an extracellular matrix protein in the laminin family. We investigated the possible involvement of gicerin in oviductal development, regeneration, and metastasis of oviductal adenocarcinomas of the chicken. In the oviductal epithelium, gicerin was expressed strongly during development, disappeared after maturation, and reappeared during regeneration. NOF was constitutively expressed in the basement membrane of the epithelium. These molecules were expressed strongly in oviductal adenocarcinomas in both primary and metastatic lesions in the mesentery. An anti-gicerin antibody inhibited the attachment of adenocarcinoma cells to the mesentery in vitro. Many cells migrated from adenocarcinoma tissues on NOF, which were inhibited by an anti-gicerin antibody. These results suggest that gicerin might play a role in oviductal development and regeneration and also in the metastasis of adenocarcinomas.

Adenocarcinoma↗
PubMed1999

Calmodulin functions as an activator of Pur alpha binding to single-stranded purine-rich DNA elements (PUR elements).

Pur alpha is a single stranded DNA-binding protein and binds to a consensus sequence (GGN)n. We have reported that the DNA-binding activity of a single stranded cyclic AMP response element-binding protein (ssCRE-BP) is suppressed in cerebellum treated chronically with morphine, ssCRE-BP is identical to Pur alpha and the DNA binding activity of Pur alpha is markedly enhanced by a heat stable activator in the nuclear extract. In this report, we purified this activator. The amino acid composition and partial amino acid sequence were determined to be identical to those of calmodulin (CaM), which enhanced the binding of GST-Pur alpha to various PUR elements in the 5' non-coding regions of the neuropeptide Y, myelin basic protein and nicotinic Ach receptor beta 4 subunit genes. The data suggest a novel gene expression pathway mediated by Ca/CaM-Pur alpha which may regulate a variety of genes in addition to those regulated through the CREB pathway.

Animals↗
PubMed1999

Expression of gicerin, a novel cell adhesion molecule, is upregulated in the astrocytes after hypoglossal nerve injury in rats.

Gicerin is an integral membrane glycoprotein which mediates cell-cell and cell-extracellular matrix (ECM) interactions in the nervous system. We studied gicerin expression in the hypoglossal nucleus post transection using in situ hybridization and immunocytochemistry. We found that hypoglossal nerve injury resulted in a significant increase in gicerin expression. Its expression levels reached peak values in reactive astrocytes surrounding axotomized motoneurons of the ipsilateral hypoglossal nucleus 14 days after hypoglossal nerve injury. The results indicate that gicerin is up-regulated during nerve regeneration, suggesting that gicerin expressed in the reactive astrocytes might be involved in the processes of nerve regeneration.

Animals↗
PubMed1999

Effects of denervation on energy metabolism of rat hindlimb muscles: application of (31)P-MRS and (19)F-MRS.

We studied the effects of denervation on the energy metabolism and peripheral circulation dynamics of rat hindlimb muscles during and after exercise. The sciatic nerves of male Wistar rats were cut to produce denervation. Energy metabolism was assessed by phosphorus-31 magnetic resonance spectroscopy (MRS), and circulation by fluorine-19 MRS. Exercise of rat hindlimb muscles was induced by electrical stimulation at 40 Hz. The inorganic phosphate (Pi) / ¿Pi + phosphocreatine (PCr)¿ ratio, an indicator of the energy level, was 0.795 immediately after denervation. The ratios 4 and 8 weeks after denervation were 0.870 and 0.853, respectively. The intracellular pH during the 4 min after initiation of stimulation was significantly reduced 4 and 8 weeks after denervation compared with the value immediately after denervation. The signal strength of the research perfluoro-carbon (FC-43; perfluorotributylamine) a measure of circulation dynamics, increased to 167% in controls during exercise, but an increase of only 134% was seen in rats 8 weeks after denervation. These results showed that the energy supply and circulation dynamics in denervated atrophic muscles decreased during exercise compared with findings in control muscles.

Animals↗
PubMed1998

Transcriptional activation of the alternative oxidase gene of the fungus Magnaporthe grisea by a respiratory-inhibiting fungicide and hydrogen peroxide.

Alternative oxidase (AOX) is dramatically induced when the fungus Magnaporthe grisea is incubated with the fungicide SSF-126, which interacts with the cytochrome bc1 complex in the electron transport system of mitochondria. A full-length cDNA for the alternative oxidase gene (AOX) was obtained, and the deduced amino acid sequence revealed marked similarity to other AOXs, but lacks two cysteine residues at corresponding sites which are conserved in plant AOXs and play essential roles in the post-translational regulation. Northern blot experiments showed that treatment of M. grisea cells with SSF-126 induces accumulation of AOX mRNA in a dose-dependent manner, and the level was correlated with the activity of alternative respiration. H2O2 also induced the accumulation of the transcript with a short half-life (<15 min). Nuclear run-on experiments showed that the AOX gene was transcribed constitutively in unstimulated cells. Cycloheximide did not change the basal level of transcription, but induced the accumulation of the transcript, indicating that active degradation of the transcript occurs by factor(s) sensitive to cycloheximide. On the other hand, SSF-126 enhanced the transcriptional activity of AOX gene threefold compared to that of control cells, and H2O2 was also potent for enhancement of the transcription. From these results, it is concluded that the respiratory inhibitor-dependent activation of the transcription is a primary determinant for the induction of alternative respiration in M. grisea. Because we have previously shown that SSF-126 treatment of M. grisea mitochondria induced the generation of superoxide, active oxygen species are thought to be signal mediators to activate AOX gene transcription in M. grisea.

Amino Acid Sequence↗
PubMed1998

Adhesive activity of gicerin, a cell-adhesion molecule, in kidneys and nephroblastomas of chickens.

Gicerin, a cell-adhesion molecule belonging to the immunoglobulin superfamily, has both homophilic and heterophilic binding activities to neurite outgrowth factor, an extracellular matrix molecule in the laminin family. Gicerin is thought to play a role in the normal development of chicken kidney, because it is expressed abundantly in the embryonic organ and only slightly in the mature organ. In this study, we have examined the adhesive activity of gicerin in the kidney to characterize its function in organogenesis. We have also examined the function of gicerin in chicken nephroblastomas ("embryonic nephromas"), which show various structures resembling those in embryonic kidneys. Immunohistochemically, the expression patterns of gicerin and neurite outgrowth factor in nephroblastomas are similar to those of embryonic kidneys. Cell-aggregation assays have shown that primary culture cells from both embryonic kidneys and nephroblastomas have strong aggregation activities, and that each aggregation is partially inhibited by gicerin antibody. In contrast, cells from adult kidney exhibit weak aggregation activity that is not inhibited by the antibody. In addition, ligand blot analysis has revealed that gicerins in embryonic kidney and nephroblastoma bind to purified neurite outgrowth factor, whereas extracts from adult kidney show no positive reaction. These findings suggest that the homophilic and heterophilic adhesive activities of gicerin are involved in the formation of both normal kidney and nephroblastoma.

Animals↗
PubMed1998

Neurite promotion from ciliary ganglion neurons by gicerin.

Gicerin is a cell adhesion molecule of an immunoglobulin superfamily member and transiently expressed on the surface of neurons such as retinal ganglion cells during synaptogenesis. Gicerin is a receptor for NOF (neurite outgrowth factor) that belongs to the laminin family, and mediates neurite extension induced by NOF. As we have reported, gicerin also exhibits homophilic cell adhesion activity, we compared the patterns of extending neurites induced by homophilic and heterophilic cell adhesion activities of gicerin using ciliary ganglion (CG) neurons. CG neurons expressed gicerin and extended neurites on a feeder layer of gicerin-transfected cells, suggesting a neurite extension by gicerin-gicerin (homophilic) interaction. We found that CG neurons cultured on gicerin-transfected cells extended slightly branched neurites, while those cultured on NOF-coated substratum extended many long branched neurites. It is suggested that neurites induced by homophilic or heterophilic cell adhesion activities of gicerin differ in the length and branching.

Animals↗
PubMed1998

A single stranded DNA-binding protein, ssCRE-BP/Pur alpha, in rat lung and its increase in allergic airway inflammation.

ssCRE-BP/Pur alpha is a single stranded DNA-binding protein and may be involved in gene replication and transcription and in the development of morphine dependence. We found a ssCRE-BP/Pur alpha (45 kDa) in rat lung that was larger than those (40 kDa) identified in rat and mouse brains and mouse lung. Immunohistochemistry showed that ssCRE-BP/Pur alpha is primarily distributed in the lung epithelium. As allergic inflammation induces various gene expressions, we investigated the changes of Pur alpha during airway inflammation. Ovalbumin-sensitized rats were used for inducing allergic airway inflammation. The expression and DNA-binding activity of 45-kDa ssCRE-BP/Pur alpha were significantly increased in the sensitized rat lungs 24 hr after antigen challenge, but not in those of rats nonsensitized or sensitized with ovalbumin and challenged with saline. Immunohistochemistry and in situ hybridization demonstrated that the vascular endothelial cells and numerous infiltrated eosinophils around the airways were stained with anti-Pur alpha antibody. These data suggest that rat lung and the eosinophils contain a 45-kDa ssCRE-BP/Pur alpha that is increased when airway inflammation occurs.

Animals↗
PubMed1997

Gicerin, a cell adhesion molecule, participates in the histogenesis of retina.

Gicerin is a novel cell adhesion molecule that belongs to the immunoglobulin superfamily. Gicerin protein adheres to neurite outgrowth factor (NOF), an extracellular matrix protein in the laminin family, and also exhibits homophilic adhesion. Heterophilic adhesion of gicerin to NOF is thought to play an active role in neurite outgrowth of developing retinal cells in vitro. In this study, we examined the adhesion activity of gicerin during the retinal development of Japanese quail using an antibody directed against gicerin, to elucidate the biological importance of gicerin in retinal histogenesis. Immunohistochemical and Western blot analysis showed that gicerin was highly expressed in the developing retina but suppressed in the mature retina. The aggregation of neural retinal cells from 5-day embryonic quail retina was significantly inhibited when incubated with a polyclonal antibody to gicerin, suggesting that gicerin protein participates in the adhesion of neural retinal cells of the developing retina. Furthermore, histogenesis of retina both in the organ cultures and in ovo embryos was severely disrupted by incubation with a gicerin antibody. These findings provide evidence that gicerin plays an important role in retinal histogenesis.

Animals↗
PubMed1997

Motivation-dependent activity in the dorsolateral part of the prefrontal cortex in the monkey.

Field potentials were recorded on self-paced hand and mouth movements with implanted electrodes on the surface and at 2.0-3.0 mm depth in respective cortical areas in seven monkeys. Surface-negative (s-N), depth-positive (d-P) premovement slow potentials were recorded in the prefrontal cortex only when the movements were performed with an intense motivation for a reward. Such a motivation-dependent activity was mainly obtained in the rostral bank of the arcuate sulcus on both sides (except for the inferior limb of the arcuate sulcus in the left hemisphere). Three of the seven monkeys were also tasked with visuo-initiated hand movements. As motivation for reward decreased, s-N, d-P potentials at a latency of about 80 ms after stimulus onset became gradually smaller in the rostral bank of the arcuate sulcus in the right hemisphere. These facts suggest that motivation-dependent activity is represented in the dorsolateral part of the prefrontal cortex in monkeys, and that the cortical part is involved in motivational functions as well as in cognitive functions.

Animals↗
PubMed1997

Mutants of the phytopathogenic fungus magnaporthe grisea deficient in alternative, cyanide-resistant, respiration

The phytopathogenic fungus Magnaporthe grisea has a cyanide-resistant respiratory pathway. The fungicide SSF-126 ((E)-2-methoxyimino-N-methyl-2-(2-phenoxyphenyl) acetamide) blocks the cytochrome electron transport of M. grisea and induces the alternative respiratory pathway. Twelve mutants of M. grisea more susceptible to SSF-126 than wild type were identified after N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis. Five mutants retained a reduced alternative respiration activity, and seven mutants lacked alternative pathway activity. A monoclonal antibody against the maize alternative oxidase cross-reacted against a 40-kDa mitochondrial protein of M. grisea, indicating that the 40-kDa protein is an alternative oxidase. Immunoblot analysis indicated that the seven completely deficient mutants grouped into two classes: four mutants produced the 40-kDa proteins while the other three mutants failed to produce the functional protein. Copyright 1997 Academic Press. Copyright 1997 Academic Press

Journal Article↗
PubMed1997

Analysis of the T beta gamma-binding domain of MEKA/phosducin.

MEKA/phosducin, a 33 kDa phosphoprotein in the photoreceptor cell, associates with transducin beta gamma (T beta gamma) with its N-terminal domain (N-terminal 105 amino acids of MEKA), and translocates T beta gamma from the photoreceptor disc membrane to the soluble fraction. The present study further localized the T beta gamma-binding domain to aa 17-105 of MEKA, and showed that the activity of MEKA to translocate T beta gamma depends on the domain. A series of deletion mutant MEKA proteins were prepared to investigate the domain of MEKA which binds to and translocates T beta gamma. Both binding and translocation activities were not impaired by the deletion of the N-terminal 16 amino acids of MEKA, but completely abolished by further deletion to 42Val. Although anti-MEKA serum inhibited the T beta gamma-MEKA association, the antiserum absorbed with a recombinant peptide corresponding to aa 17-105 of MEKA did not, confirming that aa 17-105 of MEKA directly interacts with T beta gamma.

Amino Acid Sequence↗
PubMed1997

Characterization of a nuclear factor that enhances DNA binding activity of SSCRE-BP/PUR alpha, a single-stranded DNA binding protein.

Pur alpha has been identified as a single-stranded DNA binding protein that specifically binds to the purine-rich strand present in the DNA replication initiation zone of the human c-myc gene. We have previously demonstrated that chronic morphine treatment decreases the DNA binding activity of ssCRE-BP (single-stranded cyclic AMP response element-binding protein), which has been shown to be identical to pur alpha by cDNA cloning, and is abundant in the brain. In this report we identified an activator of ssCRE-BP/pur alpha in the brain and characterized it. Although purified ssCRE-BP/pur alpha or its GST-fusion protein exhibited very low DNA binding activities, they were markedly enhanced by including nuclear extract in the binding assay. The enhanced binding activity is trypsin-sensitive, heat-stable and has a molecular weight of approximately 66 kDa. Casein could substitute for the activator and increased the DNA binding activity of ssCRE-BP/pur alpha by one order. A series of deletion mutants were prepared in order to determine the DNA binding and activator interacting domains, and both of them were found to reside in AA 50-215 of ssCRE-BP/pur alpha. These data suggest that the DNA binding activity of ssCRE-BP/pur alpha is augmented by a nuclear protein, which may modulate the ssCRE-BP/pur alpha activity to develop morphine dependence and tolerance.

Animals↗
PubMed1997

Expression of neurite outgrowth factor and gicerin during inner ear development and hair cell regeneration in the chick.

Several cell adhesion molecules are expressed in the developing inner ear. The present study focused on gicerin, a novel member of the immunoglobulin superfamily, in an attempt to improve our understanding of the development and regeneration of chick inner ear. Gicerin is known to homophilically interact with itself and to bind to neurite outgrowth factor (NOF). The data collected herein show that gicerin is highly expressed in auditory epithelium and acoustic ganglion during early embryogenesis. The immunoreactivity of gicerin in the auditory epithelium decreases more rapidly than that in the acoustic ganglion as the mature hair cells become distinguishable. At the post-hatch stage, the expression of gicerin is not observed. In contrast, NOF was expressed on the basement membranes around the auditory epithelium, and in the acoustic ganglion during development and after birth, but not in the auditory epithelium. Following noise damage, gicerin is transiently re-expressed on the damage receptor epithelium when active cell proliferation is observed in the epithelium. This positive reaction immediately disappears as immature short hair cells appear. These results suggest that gicerin may be associated with cell proliferation in the auditory epithelium, and play a role in neurite extension of the acoustic ganglion cells in conjunction with NOF.

Acoustic Stimulation↗