Search PubMed⌕ Search

Biomedical subjects

Noriko Miyake

Publications and source records attributed to Noriko Miyake.

At least 19 recordsLinked to original sources
PubMed2006

Array comparative genomic hybridization analysis in first-trimester spontaneous abortions with 'normal' karyotypes.

Array comparative genomic hybridization (array CGH) analysis was conducted in chorionic villous samples from 20 first-trimester spontaneous abortions with G-banding normal chromosomes. A microarray, containing 2,173 BAC clones and covering the whole genome with a 1.5-Mb resolution, was constructed and used in the analysis. Two deletions were identified: a 1.4-Mb deletion at 3p26.2-p26.3 and a 13.7-Mb deletion at 13q32.3-qter. Reexamination of chromosome preparations from the sample with the 13.7-Mb deletion documented a mixture of cells with the 13q- chromosome and those with 46,XX chromosomes, the latter of which are likely to have been derived from contaminating decidual cells. This left the 1.4-Mb 3p deletion as the only instance with submicroscopic imbalance detected, giving a frequency of 1 in 19 (5%) G-banding normal abortions.

Abortion, Spontaneous↗
PubMed2006

PML-RARalpha and AML1-ETO translocations are rarely associated with methylation of the RARbeta2 promoter.

The acute promyelocytic leukemia-specific PML-RARalpha fusion protein is a dominant-negative transcriptional repressor of retinoic acid receptor (RAR) target genes, which recruits HDAC and corepressor proteins and inhibits coactivators. Another oncogenic transcription factor, AML1-ETO, was proposed to cause an HDAC-dependent repression of RAR target genes. The RAR target RARbeta2 gene has been reported to be frequently silenced by hypermethylation in many types of cancer cells. We examined the methylation status of the RARbeta2 and asked if demethylation could reverse ATRA resistance in ATRA-resistant PML-RARalpha and AML1-ETO-positive cells. PML-RARalpha positive NB4 and its ATRA-resistant subvariant MR2 and AML1-ETO expressing Kasumi-1 cells had heterozygous methylation of RARbeta2. Although DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine partially reversed RARbeta2 CpG methylation in these cells, it did not significantly enhance ATRA-induced RARbeta2 mRNA expression and induction of maturation. However, the histone acetylase inhibitor SAHA combined with ATRA significantly reactivated RARbeta2 mRNA both in NB4 and MR2 cells with degradation of PML-RARalpha, which was associated with maturation. In contrast, SAHA did not affect AML1-ETO levels and failed to induce RARbeta2 expression and maturation in Kasumi-1 cells. In primary AML samples, RARbeta2 expression was uniformly low; however, no specific correlation was observed between the methylation of the RARbeta2 gene and expression of the fusion proteins, PML-RARalpha, and AML1-ETO. These results demonstrate that oncogenic PML-RARalpha and AML1-ETO translocations are rarely associated with RARbeta2 promoter methylation in primary AML samples.

Antineoplastic Agents↗
PubMed2006

Microarray comparative genomic hybridization (CGH)-based prenatal diagnosis for chromosome abnormalities using cell-free fetal DNA in amniotic fluid.

Cell-free fetal DNA (cffDNA) in the supernatant of amniotic fluid, which is usually discarded, can be used as a sample for prenatal diagnosis. For rapid prenatal diagnosis of frequent chromosome abnormalities, for example trisomies 13, 18, and 21, and monosomy X, using cffDNA, we have developed a targeted microarray-based comparative genomic hybridization (CGH) panel on which BAC clones from chromosomes 13, 18, 21, X, and Y were spotted. Microarray-CGH analysis was performed for a total of 13 fetuses with congenital anomalies using cffDNA from their uncultured amniotic fluid. Microarray CGH with cffDNA led to successful molecular karyotyping for 12 of 13 fetuses within 5 days. Karyotypes of the 12 fetuses (one case of trisomy 13, two of trisomy 18, two of trisomy 21, one of monosomy X, and six of normal karyotype) were later confirmed by conventional chromosome analysis using cultured amniocytes. The one fetus whose molecular-karyotype was indicated as normal by microarray CGH actually had a balanced translocation, 45,XY,der(14;21)(q10;q10). The results indicated that microarray CGH with cffDNA is a useful rapid prenatal diagnostic method at late gestation for chromosome abnormalities with copy-number changes, especially when combined with conventional karyotyping of cultured amniocytes.

Amniotic Fluid↗
PubMed2006

BAC array CGH reveals genomic aberrations in idiopathic mental retardation.

Array using 2,173 BAC clones covering the whole human genome has been constructed. All clones spotted were confirmed to show a unique signal at the predicted chromosomal location by FISH analysis in our laboratory. A total of 30 individuals with idiopathic mental retardation (MR) were analyzed by comparative genomic hybridization using this array. Three deletions, one duplication, and one unbalanced translocation could be detected in five patients, which are likely to contribute to MR. The constructed array was shown to be an efficient tool for the detection of pathogenic genomic rearrangements in MR patients as well as copy number polymorphisms (CPNs).

Chromosome Aberrations↗
PubMed2005

Polyhistidine tract expansions in HOXA1 result in intranuclear aggregation and increased cell death.

HOXA1 gene is part of a cluster of homeotic selector genes that regulates the anteroposterior patterning of mammals during embryonic development. HOXA1 encodes two alternatively spliced mRNAs with two isoforms, A and B, the former contains the homeodomain and expressed in early embryonic development. HOXA1 contains a string of 10 histidine repeats. However, individuals heterozygous for 7, 9, 11, and 12 histidine repeat variants were present among the Japanese population, notably in some autism cases. To determine the biological implications of the different polyhistidine repeat lengths, we expressed these variants in COS-7 and a human neuroblastoma cell line (SK-N-SH). Expression of expanded variants of HOXA1 isoform A, containing 11 and 12 polyhistidine, resulted in early and great degree of protein aggregation in the nucleus. This aggregation resulted in accelerated cell death in cells expressing 11 and 12 expanded variants compared to those transfected with 7 and 10 polyhistidine variants. Furthermore, we showed that these aggregates were ubiquitinated and were inhibited by a histidine-modifying compound, DEPC. These data suggest that HOXA1 protein with polyhistidine tract expansions misfold, aggregate, and have a toxic effect on cell.

Animals↗
PubMed2005

HOXB4-induced self-renewal of hematopoietic stem cells is significantly enhanced by p21 deficiency.

Enforced expression of the HOXB4 transcription factor and downregulation of p21(Cip1/Waf) (p21) can each independently increase proliferation of murine hematopoietic stem cells (HSCs). We asked whether the increase in HSC self-renewal generated by overexpression of HOXB4 is enhanced in p21-deficient HSCs. HOXB4 was overexpressed in hematopoietic cells from wild-type (wt) and p21-/- mice. Bone marrow (BM) cells were transduced with a retroviral vector expressing HOXB4 together with GFP (MIGB4), or a control vector containing GFP alone (MIG) and maintained in liquid culture for up to 11 days. At day 11 of the expansion culture, the number of primary CFU-GM (colony-forming unit granulocyte-macrophage) colonies and the repopulating ability were significantly increased in MIGB4 p21-/- BM (p21B4) cells compared with MIGB4-transduced wt BM (wtB4) cells. To test proliferation of HSCs in vivo, we performed competitive repopulation experiments and obtained significantly higher long-term engraftment of expanded p21B4 cells compared with wtB4 cells. The 5-day expansion of p21B4 HSCs generated 100-fold higher numbers of competitive repopulating units compared with wtMIG and threefold higher numbers compared with wtB4. The findings demonstrate that increased expression of HOXB4, in combination with suppression of p21 expression, could be a useful strategy for effective and robust expansion of HSCs.

Animals↗
PubMed2005

Molecular characterization of del(8)(p23.1p23.1) in a case of congenital diaphragmatic hernia.

A 36-week-old fetus was referred to the medical center because of his cystic mass and fluid in left thoracic cavity, and was delivered by cesarean section to manage neonatal problems at 37 weeks of gestation. Emergent surgical repair of the left diaphragmatic hernia was performed, but severe hypoxia persisted, and he expired on the following day. Chromosome analysis of cultured amniotic fluid cells indicated 46,XY,del(8)(p23.1p23.1). This is the fourth case of 8p23.1 deletion associated with diaphragmatic hernia. Microarray comparative genomic hybridization analysis using DNA of cultured amniotic fluid cells showed that six clones were deleted, which were mapped to the region between two low copy repeats (LCRs) at 8p23.1 previously described. Microsatellite analysis revealed that the deletion was of paternal origin, and his parents did not carry 8p23.1 polymorphic inversion. These data strongly suggested that the 8p23.1 interstitial deletion should have arisen through a different mechanism from that of inv dup del(8p) whose structural abnormality is always of maternal origin and accompanies heterozygous 8p23.1 polymorphic inversion in mother.

Adult↗
PubMed2005

[Microarray CGH].

Explore the source record for details and available documents.

Genetic Predisposition to Disease↗
PubMed2004

Molecular characterization of inv dup del(8p): analysis of five cases.

We analyzed five patients with inverted duplication deletion of 8p [inv dup del(8p)] using fluorescence in situ hybridization (FISH) and short tandem repeat polymorphism (STRP) analysis. In all patients, inv dup del(8p) consisted of a deleted distal segment, an intact in-between segment, and a duplicated proximal segment. In all of them, the proximal breakpoint of the deletion and one of the breakpoints of the duplication were identical, each located at one of the two olfactory receptor gene clusters at 8p23. FISH analysis showed all their mothers to be heterozygous carriers of an 8p23 inversion [inv(8)(p23)]. STRP analysis indicated that the deletions occurred in maternally derived chromosomes. The duplicated segments had two copies of maternal, either heterozygous or homozygous alleles. These findings support and reinforce those in 16 patients with inv dup del(8p) and their parents by Floridia et al. [1996: Am J Hum Genet 58:785-796] and subsequent additional studies of 10 of them by Giglio et al. [2001: Am J Hum Genet 68:874-883]. Based on these findings, we propose a model for the inv dup del(8p) formation. The inverted segment and its normal counterpart in inv(8)(p23) heterozygous carrier mothers form a loop at the pachytene period of meiosis I. Inv dup del(8p) with heterozygous duplication is formed through at least one meiotic recombination within the loop. Inv dup del(8p) with the homozygous duplication arises through two meiotic recombinations on the inv(8)(p23) chromosome (one within the loop and the other between the loop and centromere). Subsequent rescue by eliminating a part of the duplicated segment and a centromere enables formation of viable inv dup del(8p). The frequency of the inv(8)(p23) allele is 39% in a normal Japanese population, comparable to 26% in Europeans Giglio et al. [2001: Am J Hum Genet 68:874-883]. The proposed mechanism of formation of inv dup del(8p) requires two independent events (a recombination within the loop and subsequent rescue), which may explain its rarity.

Abnormalities, Multiple↗
PubMed2004

Phenotype-genotype correlation in two patients with 12q proximal deletion.

Proximal 12q deletion is a very rare chromosomal abnormality. Only five cases have been reported. Among the five, an Argentinian patient (Case 1) with del(12)(q11q13) and a Japanese patient (Case 2) with del(12)(q12q13.12) were analyzed because they shared several clinical features: growth and psychomotor developmental delay; strabismus; broad and short nose with anteverted nostrils; high, arched palate; large, lowset ears; widely set nipples; short fingers and clinodactyly of fifth fingers; and abnormality of the second and third toes. To clarify the correlation between the deleted genes and their phenotypes, we delimited their deleted regions by fluorescence in situ hybridization (FISH). The overlapped region in the deletions spanned 6.2 Mb where at least 15 genes were predicted to localize on the current human genome database. Among them, YAF2 and AMIGO2 were the most plausible candidates to affect growth and psychomotor retardation, respectively, in both cases. Regarding unique symptoms in each case, congenital fibrosis of the extraocular muscles found only in Case 1 may be caused by KIF21A deletion and hearing loss and cleft palate in Case 2 by COL2A1 defect.

Abnormalities, Multiple↗
PubMed2003

Intracellular mRNA cleavage by 3' tRNase under the direction of 2'-O-methyl RNA heptamers.

Mammalian tRNA 3' processing endoribonuclease (3'-tRNase) can cleave any RNA at any site under the direction of small guide RNA (sgRNA) in vitro. sgRNAs can be as short as heptamers, which are much smaller than small interfering RNAs of approximately 21 nt. Together with such flexibility in substrate recognition, the ubiquity and the constitutive expression of 3'-tRNase have suggested that this enzyme can be utilized for specific cleavage of cellular RNAs by introducing appropriate sgRNAs into living cells. Here we demonstrated that the expression of chloramphenicol acetyltransferase can be downregulated by an appropriate sgRNA which is introduced into Madin-Darby canine kidney epithelial cells as an expression plasmid or a synthetic 2'-O-methyl RNA. We also showed that 2'-O-methyl RNA heptamers can attack luciferase mRNAs with a high specificity and induce 3'-tRNase-mediated knock-down of the mRNAs in 293 cells. Furthermore, the MTT cell viability assay suggested that an RNA heptamer can downregulate the endogenous Bcl-2 mRNA in Sarcoma 180 cells. This novel sgRNA/3'-tRNase strategy for destroying specific cellular RNAs may be utilized for therapeutic applications.

Animals↗
PubMed2003

Preferential paternal origin of microdeletions caused by prezygotic chromosome or chromatid rearrangements in Sotos syndrome.

Sotos syndrome (SoS) is characterized by pre- and postnatal overgrowth with advanced bone age; a dysmorphic face with macrocephaly and pointed chin; large hands and feet; mental retardation; and possible susceptibility to tumors. It has been shown that the major cause of SoS is haploinsufficiency of the NSD1 gene at 5q35, because the majority of patients had either a common microdeletion including NSD1 or a truncated type of point mutation in NSD1. In the present study, we traced the parental origin of the microdeletions in 26 patients with SoS by the use of 16 microsatellite markers at or flanking the commonly deleted region. Deletions in 18 of the 20 informative cases occurred in the paternally derived chromosome 5, whereas those in the maternally derived chromosome were found in only two cases. Haplotyping analysis of the marker loci revealed that the paternal deletion in five of seven informative cases and the maternal deletion in one case arose through an intrachromosomal rearrangement, and two other cases of the paternal deletion involved an interchromosomal event, suggesting that the common microdeletion observed in SoS did not occur through a uniform mechanism but preferentially arose prezygotically.

Abnormalities, Multiple↗