Search PubMed⌕ Search

Biomedical subjects

N Niikawa

Publications and source records attributed to N Niikawa.

At least 145 records · Page 8Linked to original sources
PubMed1996

[CATCH22 syndrome].

Explore the source record for details and available documents.

Abnormalities, Multiple↗
PubMed1995

cDNA sequence and chromosomal localization of a novel human protein, RBQ-1 (RBBP6), that binds to the retinoblastoma gene product.

We have previously isolated cDNA of a novel protein (RBQ-1, HGMW-approved symbol RBBP6) that binds to the retinoblastoma gene product (pRB). Total nucleotide sequence of the cDNA has now been determined. It encoded a protein of 140 kDa that consists of 948 amino acids and contains multiple repeated sequences like SRS, YRE, and VPPP. The region used for pRB binding was identified on a small region near the C-terminus. We have mapped this gene to 16p11.2-p12 using polymerase chain reaction analysis on a human-hamster hybrid cell panel and chromosomal fluorescence in situ hybridization.

Amino Acid Sequence↗
PubMed1995

Genetic association between chromosome 8 microsatellite (MS8-134) and Werner syndrome (WRN): chromosome microdissection and homozygosity mapping.

Werner syndrome (WRN) is an autosomal recessive disorder characterized by premature aging that has been mapped to the short arm of chromosome 8, 8p11.2-p12. To refine the genetic map around the WRN region, we have isolated eight microsatellites for this region from a microdissection library. We typed members of Japanese families with WRN on the basis of homozygosity mapping analysis. There was no obligate recombination between the WRN locus and microsatellite clone, MS8-134 (D8S1055). The maximum lod score was 20.28 at theta = 0.00. Alleles for MS8-134 showed association with WRN in a case-control study (OR = 3.55, 95% CI 1.56-8.07, P < 0.01). Such microsatellites from a microdissection library of the definite chromosome region may be useful for positional cloning of the WRN gene.

Base Sequence↗
PubMed1995

Molecular cloning of a human protein that binds to the retinoblastoma protein and chromosomal mapping.

We have isolated distinct clones for cellular proteins that bind to the retinoblastoma protein by direct screening of cDNA expression libraries using purified pRB as a probe. The total nucleotide sequence of one of these clones, RBQ-3, was determined and found to encode a protein of 66 kDa localized in the nucleus. The RBQ-3 preferentially binds to underphosphorylated pRB. The region used for binding to this protein was mapped to the E1A-binding pocket B of pRB, which has sequence similarity to the general transcription factor TFIIB. We have mapped the gene to 1q32 using polymerase chain reaction analysis on a human-hamster hybrid cell panel and chromosomal fluorescence in situ hybridization.

Amino Acid Sequence↗
PubMed1995

Heme requirement for production of active endothelial nitric oxide synthase in baculovirus-infected insect cells.

We have cloned cDNAs encoding endothelial nitric oxide synthase (ecNOS) from a human fetal liver cDNA library. Overproduction of ecNOS in a baculovirus/insect cell expression system in conventional medium yielded a large amount of ecNOS protein localized in particulate components, but ecNOS activity was low. This activity was increased by addition of hemin to 2.5-fold. While a precursor for heme biosynthesis increased the activity, inhibitors of heme biosynthesis reduced the ecNOS activity to 50% without affecting the level of enzyme. After extraction of cells with 1% Triton X-100, ecNOS protein was purified by column chromatography. The resultant ecNOS required supplementation with cofactors for activity, but it did not require hemin. Binding of a protoporphyrin IX heme was confirmed by a pyridine hemochrome assay.

Amino Acid Oxidoreductases↗
PubMed1995

DNA-based prenatal carrier detection for group A xeroderma pigmentosum in a chorionic villus sample.

DNA-based prenatal carrier detection of group A xeroderma pigmentosum (XP-A) is reported. Chorionic villus sampling was done at the tenth gestational week in a pregnant woman whose first child suffers from XP-A. Genomic DNAs from the villi, proband, and parents were PCR (polymerase chain reaction)-amplified using three sets of primers, because the PCR and a subsequent enzyme digestion with HphI, AlwNI, or MseI may detect the three most frequent mutations of the XP-A complementing gene (XPAC) in Japanese XP-A patients. The results showed that the proband is a homozygote and that the parents and fetus are heterozygotes for a base substitution at the 3' acceptor site of intron 3 of XPAC, indicating that the fetus is a healthy carrier of XP-A. This is the first case of prenatal carrier detection of the disorder.

Base Sequence↗
PubMed1995

Isolation and characterization of a novel gene deleted in DiGeorge syndrome.

The region commonly deleted in DiGeorge syndrome (DGS) has been localized at 22q11.1-q11.2 with the aid of a high resolution banding technique. A 22q11 specific plasmid library was constructed with a microdissection and microcloning method. Dosage analysis proved three of 144 randomly selected microclones to detect hemizygosity in two patients with DGS. Two of the clones were found to contain independent low-copy-number repetitive sequences, all of which were included in the region deleted in the DGS patients. Screening of the cosmid library and subsequent cosmid walking allowed us to obtain two cosmid contigs corresponding to the microclones within the deletion (contig 1 and contig 2), whose order fluorescence in situ hybridization identified as centromere-contig 1-contig 2-telomere on 22q. By direct selection strategy using one of the cosmids of contig 1, a 4.3 kb cDNA was obtained from fetal brain cDNA library. Sequence analysis of the cDNA revealed an open reading frame encoding 552 amino acids which had several characteristics of DNA-binding proteins. The gene, designated LZTR-1, which was transcribed in several essential fetal organs, proved to be hemizygously deleted in seven of eight DGS patients or its variants, but not in one DGS patient and GM00980. Although LZTR-1 does not locate in the shortest region of overlap, several of its structural characteristics identifying it as transcriptional regulator suggest that it plays a crucial role in embryogenesis and that haploinsufficiency of this gene may be partly related to the development of DGS.

Amino Acid Sequence↗
PubMed1995

Fifty novel sequence-tagged sites (STSs) on human chromosome 11q13.4-->q25 identified from microclones generated by microdissection.

Fifty sequence-tagged sites (STSs) from human chromosome region, 11q13.4-->q25 were identified in microdissection-generated microclones. From a total of 124 single-copy microclones obtained from regions 11q14-->q22 and 11q23-->q25, 59 were sequenced, and a PCR primer pair was designed for each of them. Fifty of the 59 clones were mapped to regions ranging from 11q13.4 to 11q25 by means of PCR on a somatic hybrid cell panel with various deletions of the long arm of human chromosome 11. These STSs will contribute to the construction of physical cosmid/YAC maps representing the chromosome regions. They are also useful for analysis of chromosome aberrations, such as translocations, inversions or marker chromosomes.

Base Sequence↗