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Y Hotta

Publications and source records attributed to Y Hotta.

At least 37 records · Page 2Linked to original sources
PubMed2000

Novel mutations in the myocilin gene in Japanese glaucoma patients.

Myocilin is a gene responsible for juvenile onset primary open angle glaucoma (POAG) mapped as the GLC1A locus and, many mutations have been reported worldwide. Some mutations were found not only in patients with juvenile onset POAG, but also in patients with late onset POAG and in patients with normal tension glaucoma. To investigate the mutation prevalence in Japan, we performed a mutation analysis in 140 unrelated Japanese patients. We have identified the 10 sequence variants, of which four were highly probable for disease-causing mutations (Arg46ter, Arg158Gln, Ile360Asn, and Ala363Thr), and six polymorphisms (Gln19His, Arg76Lys, Asp208Glu, Val439Val, Arg470His, and Ala488Ala). Thus, myocilin mutations were found at the rate of 4/140 (2.9%) probands, similar to previous reports with other ethnic populations.

Adult↗
PubMed2000

Q118X mutation of M1S1 gene caused gelatinous drop-like corneal dystrophy: the P501T of BIGH3 gene found in a family with gelatinous drop-like corneal dystrophy.

PURPOSE: To analyze BIGH3 and M1S1 genes in two Japanese brothers with gelatinous drop-like corneal dystrophy and five unaffected family members. METHODS: DNA was extracted, and each part of the two genes was amplified and directly sequenced. RESULTS: On the BIGH3 gene, a heterozygous P501T mutation was found in the elder brother and three unaffected family members. On the M1S1 gene, both brothers with gelatinous drop-like corneal dystrophy showed a homozygous Q118X mutation, whereas all unaffected members were heterozygous. CONCLUSIONS: The Q118X mutation of M1S1 gene caused gelatinous drop-like corneal dystrophy. Although the P501T of the BIGH3 gene found in this pedigree was precisely the one reported for lattice corneal dystrophy IIIA, no clinical feature was shown, even in the 85-year-old father. This fact shows that the P501T mutation for LCDIIIA has low penetrance.

Adult↗
PubMed2000

A case of juvenile retinoschisis diagnosed by analysis of the XLRS 1 gene

Background: We report on a 3-year-old boy who was first diagnosed with retinal detachment and macular hole and received surgical treatment. X-linked juvenile retinoschisis was determined by DNA analysis.Case: Past or family history was not recognized. There was left macular hole but no typical spoke-like foveal retinoschisis was observed in either eye. We could not diagnose the case as X-linked juvenile retinoschisis because there was no family history of it, central foveal reflex was observed in the right eye with corrected visual acuity of 1.2, and no abnormality was recorded in the electroretinogram. High molecular weight DNA was extracted from peripheral leukocytes, and the XLRS 1 gene was analyzed. Hemizygous missense mutation, Arg102Gln, was detected. We diagnosed the disease as X-linked juvenile retinoschisis because the Arg102Gln mutation was detected in a family in Germany, two families in the United Kingdom, and two families in the USA.Conclusion: XLRS 1 gene analysis is useful if the diagnosis is difficult clinically due to aytpical clinical findings.

Journal Article↗
PubMed2000

Six different mutations of TGFBI (betaig-h3, keratoepithelin) gene found in Japanese corneal dystrophies.

PURPOSE: To investigate mutations of the human transforming growth factor beta-induced gene (TGFBI), transforming growth factor-beta-induced gene product (betaig-h3, keratoepithelin), in Japanese patients with Avellino corneal dystrophy (ACD), lattice corneal dystrophy (LCD), granular corneal dystrophy (GCD), and Reis-Bücklers corneal dystrophy (RBCD). METHODS: Genomic DNA was extracted from the peripheral blood of 75 patients and 7 unaffected relatives from 60 families with ACD, 34 patients and 8 unaffected relatives from 21 families with LCD, 4 patients and 4 unaffected relatives from 4 families with GCD, and 4 patients and an unaffected relative from 3 families with RBCD. Fifty normal volunteers served as controls. Exons 4, 11, and 12 of the TGFBI gene were amplified by polymerase chain reaction and were directly sequenced. RESULTS: Six different heterozygous missense mutations were detected in codons R124, L518, L527, and R555 of the TGFBI gene in the 117 patients from 88 families. A R124H mutation was detected in the patients with ACD. A R124C mutation was detected in the patients with LCD type 1 (LCD1), L518P was in atypical LCDI, and L527R in LCD with opacities deep in stroma. A R555W mutation was detected in the patients with GCD. A R555Q mutation was detected in the patients with RBCD. CONCLUSIONS: We conclude that codons R124 and R555 of the TGFBI gene are also hot spots in Japanese patients with ACD, LCD, GCD, and RBCD. Many Japanese patients with CD had ACD with R124H mutation. GCD with R555W mutation was rare.

Codon↗
PubMed2000

Corneal amyloidosis caused by Leu518Pro mutation of betaig-h3 gene.

AIM: To report a Japanese family diagnosed clinically as having lattice corneal dystrophy type I (LCDI) in which a Leu518Pro mutation in the betaig-h3 gene and not the R124C mutation reported previously was found. METHODS: Molecular genetic analysis was performed on DNA extracted from peripheral leucocytes from four members (three affected and one unaffected) of a family. Exon 4 of the betaig-h3 gene was amplified by PCR and directly sequenced. Histopathological study was performed on the corneal tissue from the proband obtained during deep lamellar keratoplasty. RESULTS: All the affected members were clinically diagnosed as having LCDI, and the pedigree indicated an autosomal dominant inheritance. A heterozygous single base pair transition (CTG to CCG, leucine to proline) was detected in codon 518 of the betaig-h3 gene in the three affected members, and not in the unaffected member. No mutation was found in codon 124. Amyloid deposits were observed between the collagen bundles of the corneal stroma and were seen to extend deep into the stroma. CONCLUSION: The Leu518Pro mutated betaig-h3 forms amyloidogeneic intermediates which precipitate in the cornea and gives rise to a clinical appearance of LCDI.

Adolescent↗
PubMed2000

Mechanism of glia-neuron cell-fate switch in the Drosophila thoracic neuroblast 6-4 lineage.

During development of the Drosophila central nervous system, neuroblast 6-4 in the thoracic segment (NB6-4T) divides asymmetrically into a medially located glial precursor cell and a laterally located neuronal precursor cell. In this study, to understand the molecular basis for this glia-neuron cell-fate decision, we examined the effects of some known mutations on the NB6-4T lineage. First, we found that prospero (pros) mutations led to a loss of expression of Glial cells missing, which is essential to trigger glial differentiation, in the NB6-4T lineage. In wild-type embryos, Pros protein was localized at the medial cell cortex of dividing NB6-4T and segregated to the nucleus of the glial precursor cell. miranda and inscuteable mutations altered the behavior of Pros, resulting in failure to correctly switch the glial and neuronal fates. Our results suggested that NB6-4T used the same molecular machinery in the asymmetric cell division as other neuroblasts in cell divisions producing ganglion mother cells. Furthermore, we showed that outside the NB6-4T lineage most glial cells appeared independently of Pros.

Animals↗
PubMed2000

4-hydroxynonenal induces a cellular redox status-related activation of the caspase cascade for apoptotic cell death.

4-Hydroxynonenal (HNE), a diffusible product of lipid peroxidation, has been suggested to be a key mediator of oxidative stress-induced cell death. In this study, we partially characterized the mechanism of HNE-mediated cytotoxicity. Incubation of human T lymphoma Jurkat cells with 20-50 microM HNE led to cell death accompanied by DNA fragmentation. Western blot analysis showed that HNE-treatment induced time- and dose-dependent activation of caspase-8, caspase-9 and caspase-3. HNE-induced caspase-3 processing was confirmed by a flow cytometric demonstration of increased catalytic activity on the substrate peptide. HNE treatment also led to remarkable cleavage of poly(ADP-ribose) polymerase (PARP), which was prevented by pretreatment of cells with DEVD-FMK as a caspase-3 inhibitor. The HNE-mediated activation of caspases, cleavage of PARP and DNA fragmentation were blocked by antioxidants cysteine, N-acety-L-cysteine and dithiothreitol, but not by two other HNE-reactive amino acids lysine and histidine, or by cystine, the oxidized form of cysteine. HNE rapidly decreased levels of intracellular reduced glutathione (GSH) and its oxidized form GSSG, and these were also attenuated by the reductants. Coincubation of Jurkat cells with a blocking anti-Fas antibody prevented Fas-induced but not HNE-induced activation of caspase-3. HNE also activated caspase-3 in K562 cells that do not express functional Fas. Our results thereby demonstrate that HNE triggers oxidative stress-linked apoptotic cell death through activation of the caspase cascade. The results also suggest a possible mechanism involving a direct scavenge of intracellular GSH by HNE.

Aldehydes↗
PubMed2000

A high association with cone dystrophy in Fundus albipunctatus caused by mutations of the RDH5 gene.

PURPOSE: To analyze the RDH5 gene in patients with fundus albipunctatus with and without cone dystrophy and to determine whether the disease is stationary or progressive and whether the cone dystrophy is a part of fundus albipunctatus or a separate disease. METHODS: Fourteen patients from 12 separate Japanese families with fundus albipunctatus were examined. Six of the patients from 6 families also had a cone dystrophy. Genomic DNA was extracted from leukocytes of the peripheral blood, and exons 2, 3, 4, and 5 of the RDH5 gene were amplified by polymerase chain reaction and were directly sequenced. A complete ophthalmic examination was performed including best-corrected visual acuity, slit-lamp examination, indirect ophthalmoscopy, fundus photography, and electroretinography. RESULTS: In all the patients, either a homozygous mutation or compound heterozygous mutations in the RDH5 gene were identified. The identified mutations were nucleotide position (nt) 103 G to A (Gly35Ser), nt 319 G to C (Gly107Arg), nt 394 G to A (Val132Met), nt 719 G insertion (frame shift), nt 839 G to A (Arg280His), nt 841 T to C (Tyr281His), and nt 928 C to GAAG (Leu310 to GluVal). All these mutations except the Arg280His were new. The nt 928 C to GAAG mutation was detected in patients with and without cone dystrophy. Cone dystrophy was most frequently seen in patients over 40 years old. CONCLUSIONS: Fundus albipunctatus either with or without cone dystrophy is caused by mutations of the RDH5 gene. Cone dystrophy is frequently observed in elderly patients with fundus albipunctatus. The conclusion was reached that the mutations of the RDH5 gene caused a progressive cone dystrophy as well as night blindness.

Adolescent↗
PubMed1999

Protective role of nitric oxide synthase against ischemia-reperfusion injury in guinea pig myocardial mitochondria.

In guinea-pig myocardial mitochondria preparation, lowering the Ca2+ concentration or pH level in the perfusate rapidly elevated the fura-2 Ca2+ signal ([Ca2+]m). Pretreatment with 10(-4) M L-Arg inhibited the rapid [Ca2+]m influx, whereas administration of 10(-4) M L-NAME did not, suggesting some association between nitric oxide (NO*) synthase (NOS) activation and Ca2+ kinetics in mitochondria. Immunoblotting analysis showed that endothelial (e)-NOS was present in mitochondria, but not inducible (i)-NOS or brain (b)-NOS. Electron microscopy observations revealed that the e-NOS antibody-reactive site in the mitochondria was the inner cristae. The production of reactive oxygen species and NO* in isolated mitochondria was detected by the spin trapping technique with electron paramagnetic resonance (EPR) spectrometry. Pretreatment with 10(-5) M S-nitroso-N-acetyl-DL-penicillamine (SNAP) and 10(-5) M 3-[2-Hydroxy-1-(1-methylethyl)-2-nitrosohydrazino]-1-propananin e (NOC 5), which spontaneously generate NO*, completely inhibited the [Ca2+]m uptake. In addition, N-morpholino sydnonimine hydrochloride (SIN-1) (10(-5) M), which simultaneously generates NO* as well as *O2- and peroxynitrite anion (ONOO-), inhibited the increase in [Ca2+]m. ONOO- (3 x 10(-4) M) itself also inhibited this increase. Pretreatment with the *O2(-)-scavenger manganese superoxide dismutase or catalase (200 units/ml) completely inhibited the increase in [Ca2+]m caused by lowering of either the Ca2+ concentration or the pH in the perfusate. These results suggested that the formation of reactive oxygen species promoted the [Ca2+]m influx. The agents that inhibited the [Ca2+]m influx improved contractility even in Langendorff preparations after ischemia. Based on these findings, we concluded that e-NOS exists in mitochondria and that NO* may play an important protective role in reperfusion cardiac injury after ischemia, by inhibiting the Ca2+ influx into mitochondria which are otherwise damaged by *O2-.

Animals↗
PubMed1999

REP-1 gene mutations in Japanese patients with choroideremia.

BACKGROUND: Choroideremia (CHM) is an X-linked progressive dystrophy of the choroid, retinal pigment epithelium, and retina. Recently, the REP-1 gene was isolated and the causative mutations in the gene were detected in patients with CHM. In a previous study, we described a Japanese family with CHM who had a mutation in the REP-1 gene. In the present study, we performed extensive analysis of the REP-1 gene in patients with CHM from several institutions in Japan. METHODS: Twenty-six patients with CHM and 5 unaffected females from 22 independently ascertained families were examined. Exons 1-15 of the REP-1 gene were screened by single-strand conformation polymorphism. The DNA fragments suspected of any variations were directly sequenced. RESULTS: Fifteen different mutations, including one previously reported mutation, were detected in 18 families. In addition, carrier status was proven in four unaffected females found to be heterozygous for the mutant allele. CONCLUSIONS: Fifteen different mutations of the REP-1 gene were detected in 18 Japanese families. There were no hot spots for the mutations and no missense mutations. The results show that REP-1 gene defects cause CHM in Japanese patients, and the mutations in these Japanese patients differed from the mutations reported for CHM patients in Europe, Canada, and America except for R267X and 1313delTC. These findings suggest that the mutations occurred independently in the Japanese patients.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Isolation of a LIM15/DMC1 homolog from the basidiomycete Coprinus cinereus and its expression in relation to meiotic chromosome pairing.

The Escherichia coli gene recA is essential for homologous recombination and DNA repair, and homologs have been identified in eukaryotes. A basidiomycete, Coprinus cinereus, which has many advantages for the study of meiosis, was recently reported to have a homolog of one of these, RAD51. In the yeast Saccharomyces, mutations in the RAD51 gene cause defects in both somatic and meiotic cells. Based on this finding, we screened for a meiosis-specific homolog of recA, equivalent to Lilium LIM15 or Saccharomyces DMC1, in C. cinereus, and isolated a clone containing a 1.2-kb DNA fragment from a cDNA library constructed with Coprinus poly(A)+ RNA isolated from cells undergoing meiosis. The predicted amino acid sequence was 52% identical to the putative gene product of the lily cDNA clone LIM15 and 61% identical to Saccharomyces DMC1, and showed limited sequence similarity to the products of RAD52, 55, and 57. The synchrony of meiosis in Coprinus provides an ideal system for the investigation of differential gene expression in relation to meiosis and fruiting body development. Northern analysis indicated that Coprinus LIM15/DMC1 was expressed at meiotic prophase within 8 h after the onset of karyogamy, suggesting that the gene functions mostly at the stage at which the homologous chromosomes pair, but may not be essential at the point at which they recombine. The gene is not expressed in somatic cells.

Amino Acid Sequence↗
PubMed1999

Leu518Pro mutation of the beta ig-h3 gene causes lattice corneal dystrophy type I.

PURPOSE: To describe a Japanese family with lattice corneal dystrophy type I, which segregates with a novel mutation, Leu518Pro of the beta ig-h3 gene. METHODS: DNA was extracted from leukocytes in four members (three affected and one unaffected) of a Japanese family with lattice corneal dystrophy type I. Exon 12 of the beta ig-h3 gene was amplified and analyzed with a molecular biologic method. Clinical data were also collected. RESULTS: Three generations of this family have been positively diagnosed with lattice corneal dystrophy, indicating autosomal dominant inheritance. We found a heterozygous point mutation that segregates with the disease phenotype. It was a single base-pair transition (CTG to CCG, Leu to Pro). CONCLUSION: Although it is extremely rare compared with the Arg124Cys mutation of the beta ig-h3 gene, Leu518Pro mutation of the beta ig-h3 also causes lattice corneal dystrophy type I.

Adolescent↗
PubMed1999

Rhodobacter sphaeroides mutants which accumulate 5-aminolevulinic acid under aerobic and dark conditions.

The photosynthetic bacterium Rhodobacter sphaeroides accumulates 5-aminolevulinic acid (ALA), which is a precursor in tetrapyrrole biosynthesis, under light illumination and upon addition of levulinic acid as an inhibitor of ALA dehydratase. To generate an industrial strain which produces ALA in the absence of light, we sequentially mutated R. sphaeroides CR-286 using N-methyl-N'-nitro-N-nitrosoguanidine (NTG). The mutant strains were screened by cultivating in the absence of light and assayed for ALA by the Ehrlich reaction in a 96-well microtiter plate. The mutant strain CR-386, derived from R. sphaeroides CR-286, was selected as a mutant that exhibited significant ALA accumulation. While CR-286 required light illumination for ALA production, CR-386 was able to accumulate 1.5 mM ALA in the presence of 50 mM glucose, 60 mM glycine, 15 mM levulinic acid and 1.0% (w/v) yeast extract under conditions of agitation in the absence of light. The mutant strain CR-450, derived from strain CR-386, was selected further as a mutant that exhibited significant ALA accumulation but no accumulation of aminoacetone, analogue of ALA. CR-450 accumulated 3.8 mM ALA under the same conditions. In the presence of 50 mM glucose, 60 mM glycine, 5 mM levulinic acid and 1.0% (w/v) yeast extract, the mutant strain CR-520, derived from strain CR-450, and strain CR-606, derived from strain CR-520, accumulated 8.1 mM and 11.2 mM ALA, respectively. In batch fermentation, the strain CR-606 accumulated 20 mM ALA over 18 h after the addition of glycine, levulinic acid, glucose and yeast extract.

Journal Article↗
PubMed1999

Visual impairment and REP-1 gene mutations in Japanese choroideremia patients.

Choroideremia (CHM), an X-linked recessive hereditary disease, is an intractable chorioretinal dystrophy. The rate of disease progression of CHM reportedly shows considerable variability. A number of mutations involving the gene that codes for Rab escort protein-1 (REP-1) have been detected in CHM patients. We have analyzed REP-1 gene mutations of Japanese CHM patients. The present study was designed to investigate the clinical variability and the genotype to phenotype relationship in 15 Japanese CHM patients referred to the Department of Ophthalmology of Juntendo University Hospital. The clinical investigation of visual acuity, visual field, color vision and refraction revealed inter-individual variability. Mutation analyses of the REP-1 gene revealed 10 types of mutations in 13 patients from 11 families, including an insertion, small deletions, nonsense mutations and an A to CC mutation. In 13 CHM patients with detectable REP-1 gene mutations, no relationship of genotype to phenotype was detected. At present, we consider the REP-1 genotype to be an unreliable prognostic factor for counseling of CHM patients. In two patients from one family, no mutations were detected in coding regions of the REP-1 gene. These patients may have intron mutations of the REP-1 gene, not detectable by the techniques employed in this study, or other causative genes. Both were observed to have somewhat slower disease progression than the other 13 patients. More advanced analyses are necessary to answer questions regarding the genotype-phenotype relationship in CHM patients.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Secondary mutations of mitochondrial DNA in Japanese patients with Leber's hereditary optic neuropathy.

PURPOSE: Based on studies on the pathogenesis of Leber's hereditary optic neuropathy (LHON), mitochondrial DNA (mtDNA) mutations have been divided into two types: primary and secondary. Primary mutations at nucleotide positions (nt) 11778, 3460, and 14484 can each cause LHON. Secondary mutations may be simultaneously found in LHON patients with a primary mutation, may occur at higher frequency in LHON patients than in normal controls, and may play an additional role in the pathogenesis of LHON. We examined the frequencies of secondary mutations of mtDNA at nt3394, 7444, 9438, 9804, 13708, and 15257 in 19 Japanese patients with LHON associated with primary mutations and 108 normal controls. METHODS: Mutations were determined by restriction enzyme analysis or DNA sequencing using polymerase chain reaction (PCR) products. RESULTS: One patient with an nt11778 mutation also had an nt13708 mutation. Another patient with an nt3460 mutation also had an nt7444 mutation. During DNA sequencing of the PCR fragment harboring nt3394, three novel mutations in the ND1 gene (nt3316, 3496, and 3497 mutations) were found in three patients with an nt11778 mutation. The frequency of these mutations in 108 control subjects was studied further: one (0.9%) had an nt3394 mutation, none (0%) had an nt9804 mutation, one (0.9%) had an nt13708 mutation, two (1.9%) had nt3316 mutations, one (0.9%) had an nt3496 mutation, and two (1.9%) had nt3497 mutations. CONCLUSION: It is unlikely that the frequencies of secondary mutations in Japanese patients with LHON are higher than those in normal Japanese controls. It is possible that the mutations at nt3316, 3496, and 3497 are secondary mutations of LHON.

Adult↗
PubMed1999

A novel glycine-rich protein is associated with starch grain accumulation during anther development.

LIM14, originally identified as a lily gene associated with microsporogenesis, encodes a protein which has two distinct domains, one with glycine-serine repeats and the other with a hydrophobic signal peptide at the N-terminus. The putative LIM14 protein, however, is distinct from the glycine-rich cell wall proteins which have been described before. RNA analyses indicated that the LIM14 transcript is specifically detected in the anther from zygotene to young pollen stage. By using antibodies raised against recombinant LIM14 protein, we detected anther-specific 15 kDa protein. Immunofluorescence microscopy demonstrated that the LIM14 protein is associated with starch grains in the anther wall cells just prior to microspore mitosis and then accumulates at a higher level with the starch grains of immature pollen. We tagged LIM14 with the GUS and GFP reporter genes and introduced them into tobacco BY-2 cells. Analysis of the transformed cells revealed that the chimeric proteins are functional and specifically targeted to plastids. These results indicate that LIM14 is an anther-specific protein that may play a role in starch accumulation and amyloplast differentiation during anther development and pollen formation.

Amino Acid Sequence↗