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K Yokobata

Publications and source records attributed to K Yokobata.

8 recordsLinked to original sources

The structural organization of the human skeletal muscle ryanodine receptor (RYR1) gene.

The RYR1 gene encoding the Ca2+ release channel of human skeletal muscle sarcoplasmic reticulum has been cloned and exon/intron boundaries have been determined, together with a minimum of 30 bp of intron sequence flanking each splice junction. The gene contains 106 exons, of which two are alternatively spliced. The length of the gene, determined by the alignment of 16 genomic phage clones, a cosmid clone, and several long polymerase chain reaction products, is approximately 160 kb. Exons range from 15 to 813 bp, while introns range from 85 to about 16,000 bp. Analysis of the gene has confirmed published errors in the human RYR1 cDNA and confirmed the structure of two alternatively spliced exons. The numbering of the nucleotides comprising the RYR1 cDNA and the numbering of amino acids encoded by them were corrected to account for these earlier errors and omissions. Analysis of 2.4 kb of the 5' upstream sequence indicated the presence of a CCAAT box and several Sp1 binding sites between nucleotides -200 and -60 bp, flanking the proposed transcription start site at -130 bp. Several other potential transcription factor binding sites were identified throughout the 5' sequence. Knowledge of the structure of the RYR1 gene will provide an invaluable resource for the discovery of mutations in the gene that are causal of human malignant hyperthermia and central core disease.

Amino Acid Sequence↗

Fluorescence in situ hybridization with a chromosome 21-specific cosmid contig: 1-day detection of trisomy 21 in uncultured mesenchymal chorionic villus cells.

We present a modified, fast trisomy 21 detection assay using fluorescence in situ hybridization (FISH) on uncultured mesenchymal chorionic villus cells. The whole test takes about 24 h. We used a cosmid contig as a probe and modified an in situ sample preparation method first described by Klinger et al. (1992). The assays saves time and cost of culture in comparison with a previously described trisomy 21 detection FISH assay (Bryndorf et al., 1993). A small blind clinical study comparing the modified and the previously described FISH assays using mesenchymal chorionic villus cells showed comparable results and concordance with conventional cytogenetic analysis. The frequency of nuclei with three hybridization signals from samples disomic for chromosome 21 ranged from 0 to 8 per cent with both assays, while trisomic samples had 60-80 and 54-90 per cent of the mesenchymal nuclei with three signals in the modified and previously described assays, respectively. Normal (disomic) and trisomic mesenchymal chorionic villus samples can be distinguished clearly and rapidly without culture in the modified assay.

Base Sequence↗

Isolation and ordering of bacteriophage genomic clones corresponding to two YACs from 19q13.3.

We describe a method for rapidly isolating overlapping bacteriophage clones corresponding to the genomic region cloned in a yeast artificial chromosome (YAC) that does not require sub-cloning or lambda DNA preparation. Purified YACs from 19q13.3 were used to screen a flow-sorted chromosome 19 library, and the resulting positive clones were characterized using inter-Alu PCR. In addition, aliquots of the lambda stocks were gridded out, and hybridized with probes known to be present in the YACs, thereby avoiding having to perform DNA preparations. The application of this technique in the identification of lambda clones which span the myotonic dystrophy (DM) locus on 19q13.3 is presented, and its general advantages are discussed.

Bacteriophage lambda↗

New rapid test for prenatal detection of trisomy 21 (Down's syndrome): preliminary report.

OBJECTIVE: To devise and evaluate a rapid screening method for detecting trisomy 21 (Down's syndrome) in samples of uncultured amniotic fluid cells. DESIGN: Non-radioactive in situ hybridisation with HY128, a 500,000 base pair yeast artificial chromosome probe specific for chromosome 21. Blinded study of 12 karyotypically normal amniotic fluid samples and eight samples trisomic for chromosome 21. SETTING: Cytogenetic and obstetric services at a tertiary referral centre, Copenhagen. MAIN OUTCOME MEASURES: Time necessary to complete the test. Proportion of cell nuclei containing two and three hybridisation signals in karyotypically normal and abnormal amniotic fluid samples. RESULTS: The test could be completed within three to four days after amniocentesis. In the normal samples a mean of 73% (range 61-82%) of the amniotic cell nuclei showed two hybridisation signals and 6% (0-18%) showed three signals. By contrast, among the trisomic samples 29% (19-38%) of the nuclei exhibited two signals and 48% (31-60%) showed three signals. CONCLUSION: The technique clearly distinguished between normal and trisomic samples. Prenatal diagnosis with in situ hybridisation with chromosome specific probes was fast and may make it possible to screen for selected, aneuploidies. However, the technique is still at a preliminary stage and needs further evaluation and refinement.

Amniocentesis↗