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T Orii

Publications and source records attributed to T Orii.

At least 73 records · Page 4Linked to original sources
PubMed1998

Brother/sister siblings affected with Hunter disease: evidence for skewed X chromosome inactivation.

Hunter disease is an X-linked recessive disorder caused by a deficiency of iduronate-2-sulfatase activity. We describe a pair of brother/sister siblings with a typical feature of Hunter disease (mucopolysaccharidosis type II). They had normal karyotypes but a marked deficiency of iduronate-2-sulfatase activity in both lymphocytes and fibroblasts. The molecular analysis of the iduronate-2-sulfatase gene revealed the R468L(G1403-->T) substitution in their genes. Although the sister's genomic DNA was heterozygous for the mutant allele, the sister's cDNA was found to be homogeneous for this mutation. The mother was found to be a heterozygote. The analysis of X chromosome inactivation by comparison of the methylation patterns of the androgen-receptor (AR) gene which was isolated from the sister's fibroblasts and leucocytes revealed a skewed X chromosome inactivation of the paternal allele. These findings indicate that a skewed X chromosome inactivation of the paternal gene and a point mutation in the maternal gene were responsible for the lack of iduronate-2-sulfatase activity in the sister.

Binding Sites↗
PubMed1998

Practical assay method of cytosolic acetoacetyl-CoA thiolase by rapid release of cytosolic enzymes from cultured lymphocytes using digitonin.

We designed a simple approach to determine cytosolic acetoacetyl-CoA thiolase (CT) activity for differential diagnosis of ketone body catabolic defects, using rapid cell-subfractionation of cultured lymphocytes with digitonin. Efficiency of cell subfractionation was determined by measurement of lactate dehydrogenase and citrate synthetase as marker enzymes for cytosol and organelle fractions, respectively, and confirmed by immunotitration and immunoblotting using antibodies against cytosolic and mitochondrial thiolases, respectively. In the condition of best separation taken in the presence of 1 mg/ml digitonin, acetoacetyl-CoA thiolase activities in the presence of K+ ion in the cytosol and organelle fractions were 138.3+/-39.2 and 84.0+/-16.2 nmol/min/ml, respectively. The thiolase activity in the organelle fraction was doubled by the presence of K+ ion, whereas that in the cytosol fraction was not affected. The thiolase activity in the organelle fraction was reduced by the treatment of anti-mitochondrial acetoacetyl-CoA thiolase (T2) antibody but not by anti-CT antibody. On the other hand, that in the cytosol fraction was significantly decreased by anti-CT antibody but not by anti-T2 antibody. These data suggested that T2 was collected in the organelle fraction, and that CT activity could be assessed by measurement of the thiolase activity in the cytosolic fraction. Succinyl-CoA: 3-ketoacid CoA transferase (SCOT), whose defect is the third inherited disorder of ketone body catabolism, was collected in the organelle fraction. Hence, this method will prove to be useful for accurate assessment of defects of CT as well as T2 or SCOT, all involved in ketone body catabolism.

Acetyl-CoA C-Acetyltransferase↗
PubMed1997

Isolation and characterization of peroxisome-deficient Chinese hamster ovary cell mutants representing human complementation group III.

We made use of the 9-(1'-pyrene)nonanol/ultraviolet (P9OH/UV) method and isolated peroxisome-deficient mutant cells. TKa cells, the wild-type Chinese hamster ovary (CHO) cells, CHO-K1, that had been stably transfected with cDNA encoding Pex2p (formerly peroxisome assembly factor-1, PAF-1) were used to avoid frequent isolation of the Z65-type, PEX2-defective mutants. P9OH/UV-resistant cell colonies were examined for the intracellular location of catalase, a peroxisomal matrix enzyme, by immunofluorescence microscopy and using anti-catalase antibody. As six mutant cell clones showed cytosolic catalase, there was likely to be a deficiency in peroxisome assembly. These mutants also showed the typical peroxisome assembly-defective phenotype, including significant decrease of dihydroxyacetonephosphate acyltransferase, the first step key enzyme in plasmalogen synthesis, and loss of resistance to 12-(1'-pyrene)dodecanoic acid/UV treatment. By transfection of Pex2p and Pex6p (formerly PAF-2) cDNAs and cell fusion analysis between the CHO cell mutants, two mutants, ZP104 and ZP109, were found to belong to a novel complementation group. Further complementation analysis using fibroblasts from patients with peroxisome biogenesis disorders revealed that the mutants belonged to human complementation group III. Taken together, ZP104 and ZP109 are in a newly identified fifth complementation group in CHO mutants reported to date and represent the human complementation group III.

ATPases Associated with Diverse Cellular Activitie↗
PubMed1997

Succinyl-CoA:3-ketoacid coenzyme A transferase (SCOT): development of an antibody to human SCOT and diagnostic use in hereditary SCOT deficiency.

Succinyl-CoA:3-ketoacid CoA transferase (SCOT) is a key enzyme for ketone body utilization. Hereditary SCOT deficiency in humans (McKusick catalogue number 245050) is characterized by intermittent ketoacidotic attacks and permanent hyperketonemia. Since previously-available antibody to rat SCOT did not crossreact with human SCOT, we developed an antibody against recombinant human SCOT expressed in a bacterial system. The recombinant SCOT was insoluble except under denaturing conditions. Antibody raised to this polypeptide recognized denatured SCOT and proved useful for immunoblot analysis. On immunoblots, SCOT was easily detectable in control fibroblasts and lymphocytes but was detected neither in fibroblast extracts from four SCOT-deficient patients, nor in lymphocytes from two SCOT-deficient patients. These data indicate that immunoblot analysis is useful for diagnosis of SCOT deficiency in combination with enzyme assay.

Animals↗
PubMed1997

Identification of 31 novel mutations in the N-acetylgalactosamine-6-sulfatase gene reveals excessive allelic heterogeneity among patients with Morquio A syndrome.

Mutation analysis of the N-acetylgalactosamine-6-sulfate sulfatase gene was performed in a group of 35 patients with mucopolysaccharidosis type IVA from 33 families, mainly of European origin. By nonradioactive SSCP screening, 35 different gene mutations were identified, 31 of them novel. Together they account for 88.6% of the disease alleles of the patients investigated. The vast majority of the gene alterations proved to be point mutations, 23 missense, 2 nonsense, and 3 affecting splicing. Six small deletions (1-27 bp) and one insertion were also characterized. In a Polish family, two mildly affected siblings were compound heterozygotes for R94G and R259Q. Their mother was homozygous for the latter point mutation, leading to enzyme deficiency and a borderline disease phenotype.

Adolescent↗
PubMed1997

Hunter disease in a girl caused by R468Q mutation in the iduronate-2-sulfatase gene and skewed inactivation of the X chromosome carrying the normal allele.

Hunter disease is an X-linked recessive mucopolysaccharide storage disorder caused by iduronate-2-sulfatase deficiency and is rare in females. We describe here findings in a girl with Hunter disease of the severe type. She had a normal karyotype but a marked deficiency of iduronate-2-sulfatase activity in lymphocytes and cultured fibroblasts. In a sequence analysis of the iduronate-2-sulfatase gene, evidence was obtained for the R468Q (G1403 to A) mutation, a common one in Hunter disease. RT-PCR showed her cDNA to represent only the R468Q allele, although at the genomic level she was a heterozygote with one normal allele. Her brother had the R468Q mutation, and their mother was a carrier of this mutation. The fusion products of CHO (TG(R),Neo(R)) with patient's fibroblasts cultured in HAT/G418 selective medium, carried only the maternal allele. However, in genomic DNA from the patient's fibroblasts, only the paternal allele of the androgen receptor gene, a gene subjected to differential methylation of the inactive X-chromosome, was methylated. These findings strongly suggest that the severe form of Hunter disease in this girl was the result of selective expression of the maternal allele carrying the missense mutation R468Q, which in turn resulted from skewed X inactivation of the paternal nonmutant X chromosome.

Alleles↗
PubMed1997

Fourteen novel mucopolysaccharidosis IVA producing mutations in GALNS gene.

Mucopolysaccharidosis IVA (MPS IVA) is an autosomal recessive disorder caused by a deficiency of the lysosomal N-acetylgalactosamine-6-sulfate sulfatase. Here, we report our analysis of data on 21 patients of diverse ethnic and geographic origins studied by SSCP and sequencing analysis. Sixteen mutations were detected, including 14 new mutations (11 missense, one premature termination, one splice site alteration, and one cryptic site alteration). The donor splice site mutation (IVS4 + 1G-->A) predicts that normal splicing will be abolished and that translation would lead to an immediate premature termination (W141X). Another novel nucleotide change outside the coding sequence is an intronic alteration (IVS9-42C-->T:ggtcggtgcggttggtgc) creating a potential cryptic donor site. The nucleotide sequence surrounding this alteration is highly suggestive of a consensus donor splice site. All 12 missense and nonsense mutations were shown by transient expression to abolish or greatly reduce GALNS activity, thereby providing an explanation as to why they produce MPS IVA. All mutations were readily confirmed by restriction enzyme or by allelic specific oligonucleotide analysis (ASO). These findings, coupled with previously reported mutations, bring the total of different mutations to 41 among independent families with MPS IVA, illustrating the extensive allelic heterogeneity among mutations producing MPS IVA.

Chondroitinsulfatases↗
PubMed1997

Molecular basis of Zellweger syndrome, beta-ketothiolase deficiency and mucopolysaccharidoses.

1. A human peroxisome assembly factor-1 (PAF-1) complementary DNA has been cloned that restores the morphological and biochemical abnormalities (including defective peroxisome assembly) in fibroblasts from a patient with group F Zellweger syndrome. The cause of the syndrome in this patient was a point mutation that resulted in the premature termination of PAF-1. The homozygous patient apparently inherited the mutation from her parents, each of whom was heterozygous for that mutation. Furthermore, we cloned and characterized the rat and human cDNAs for peroxisome-assembly factor-2 (PAF-2), which restores peroxisomes of the complementary group C Zellweger cells, by functional complementation, and identified two pathogenic mutations in the PAF-2 gene in two patients. 2. Seventeen mutations have been identified in 13 mitochondrial acetoacetyl-CoA thiolase-deficient patients. 3. We purified N-acetylgalactosamine-6-sulfate (GalNAc6S) sulfatase and cloned the full-length cDNA of human N-acetylgalactosamine-6-sulfate sulfatase (GALNS). The gene encoding GalNAc6S sulfatase has been localized by fluorescence in situ hybridization to chromosome 16q24, and the entire genomic gene structure has been characterized. About 40 different GALNS gene mutations have been identified in the patients with mucopolysaccharidosis IV A.

Acetyl-CoA C-Acyltransferase↗
PubMed1997

Mucopolysaccharidosis IVA: a novel splice acceptor site mutation in intron 4 of the N-acetylgalactosamine-6-sulfate sulfatase gene in an Afghanistan girl with classical Morquio disease.

We report here a novel splice site mutation in intron 4 of the gene for N-acetylgalactosamine-6-sulfate sulfatase (GALNS) in an Afghanistan girl with severe mucopolysaccharidosis IVA (classical Morquio disease). Direct sequencing revealed a homozygous G to A transition in the conserved splice acceptor site in intron 4 (cagG-->caaG: designated IVS 4(-I) G-->A) which eliminates 144 nucleotides of exon 5 in her GALNS transcript and introduces an immediate premature termination codon (at Trp 141 of exon 4). The IVS 4(-1) G-->A has not been seen in other populations and this is the first report of the molecular basis of classical Morquio disease in an Afghanistan patient.

Afghanistan↗