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Biomedical subjects

M C Yoshida

Publications and source records attributed to M C Yoshida.

At least 55 records · Page 3Linked to original sources
PubMed1995

Molecular analysis of a t(11;22) translocation junction in a case of Ewing's sarcoma.

Polymerase chain reaction (PCR)-directed sequence analysis was performed to characterize the genomic and cDNA breakpoint junctions of t(11;22) (q24;q12) translocation in a case of Ewing's sarcoma, in which the EWS gene located on chromosome 22 is rearranged with the FL11 gene located on chromosome 11. RNA-PCR revealed the novel chimeric product of EWS/FL11 gene on the derivative chromosome (der) 22, resulting from a probable fusion of EWS exon 7 to FL11 exon 9. Sequencing of the PCR-amplified genomic fragments of the fusion genes showed that the breakpoints on der(22) occurred in EWS intron 7 and, most probably, in FL11 intron 8. Those of the untranscribed counterpart on der(11) were located in the same FL11 intron and in EWS exon 11, with deletion of a considerable amount of sequences from both genes. These findings indicate asymmetric junction at the molecular level in the present t(11;22). None of the reported conserved sequences that mediate other cancer chromosome translocations was observed around the genomic junctions. Instead, a palindromic hexamer 5'-GCTAGC-3' was found to flank the breakpoints of both genes on der(22), which may have a functional significance in the genesis of the t(11;22).

Adolescent↗
PubMed1995

Simultaneous visualization of Q-bands and FISH signals using a novel fluorochrome.

We developed a new HNPP-azo dye method for detection of fluorescence in situ hybridization (FISH) signals on Q-banded chromosomes by use of a newly synthesized fluorochrome, HNPP (3-hydroxy-N-2'-biphenyl-2-naphthalenecarboxamide phosphate ester), which reacts enzymatically with alkaline phosphatase and azo dye. The FISH staining method permits simultaneous detection of orange HNPP signals on chromosomal sites labeled by Q-banding, allowing the assignment of small (440-1,200 bp) probes.

Animals↗
PubMed1995

Deletion of the Wilson's disease gene in hereditary hepatitis LEC rats.

LEC rats develop disorder of cooper metabolism and hepatitis similar to those of human Wilson's disease. We recently demonstrated that the gene responsible for hepatitis (hts) of LEC rats is homologous to Wilson's disease gene (WD). The present study showed a deletion of at least 90 base pair of WD cDNA in LEC rats, which corresponds to nucleotides 3981 to 4071 in human WD cDNA sequence. This deletion was linked with hepatic copper accumulation and hepatitis, and considered to be a primary mutation for hepatic disorder in the LEC rat. The WD gene was assigned to rat chromosome 16 at band q12.2-q12.4 by fluorescence in situ hybridization (FISH).

Animals↗
PubMed1995

Regional localization of rat and mouse protein-tyrosine phosphatase PTP alpha/LRP gene (Ptpra) by fluorescence in situ hybridization.

Protein tyrosine phosphatases (PTPases) negatively regulate the effect(s) of protein tyrosine kinases and are implicated in the regulation of a variety of biological events including cell activation, differentiation, and neoplastic transformation. To gain insight into the role(s) of the PTPases, we mapped the gene encoding for the widely expressed receptor-like protein tyrosine phosphatase PTP alpha/LRP (locus symbol Ptpra) to rat chromosome 3q36 and mouse chromosome 2G by fluorescence in situ hybridization method. These results indicate that there is a conserved syntenic group between human 20p13, rat 3q36, and mouse 2G.

Animals↗
PubMed1995

DNA fingerprinting of animal genomes by CA-repeat primed polymerase chain reaction.

CA-repeat primed polymerase chain reaction (CAP-PCR), using degenerate primers which anneal at the ends of (CA)n sequences in eukaryotic genomes, was attempted to assess its potential to monitor the genomic polymorphisms in various animals. Three mammalian, three avian, one fish and one insect species were examined and all showed primer-specific DNA fingerprints by CAP-PCR. Polymorphic bands observed in a laboratory-bred vole family were segregated in Mendelian manner. The present CAP-PCR DNA fingerprinting therefore is a simple and useful method for examining genomic variations in most animals without prerequisite knowledge of DNA sequences.

Animals↗
PubMed1995

Two Japanese wildcats, the Tsushima cat and the Iriomote cat, show the same mitochondrial DNA lineage as the leopard cat Felis bengalensis.

We previously revealed, based on mitochondrial DNA sequence analysis, that the Iriomote cat is very closely related to the leopard cat Felis bengalensis, which is widespread in Asia [24]. In this study, in order to understand the phylogenetic status of the Tsushima cat which is the other wildcat in Japan, partial sequences (402 bases) of the mitochondrial cytochrome b region were determined and compared with those of the Iriomote cat and other feline species. The phylogenetic tree of the cytochrome b sequences indicated that the Tsushima cat and the Iriomote cat have the same mitochondrial DNA lineage as the leopard cat. One or two transitional substitutions were observed among the two Japanese wildcats and the leopard cat. The divergence time (approximately 100,000 years ago) of the Tsushima cat and the leopard cat, estimated by sequence data, was in concordance with the formation date of the Tsushima Island. These results suggest that genetic drift after geographic isolation has brought fixation of some genetic and morphological characters to the Tsushima cat and the Iriomote cat, while these two Japanese wildcats are still genetically close to the continental leopard cat. Considering morphological differences and molecular phylogeny, it is reasonable for the two Japanese wildcats to be classified as two subspecies of F. bengalensis.

Animals↗
PubMed1995

[The chromosome mapping of enzymatic genes related to inborn metabolic errors].

For many reasons knowledge of the chromosomal location of genetic markers is highly desirable. The application of somatic cell genetic and molecular biology techniques to chromosome mapping has provided a rapid development of the gene map of human genome. Here, the current status of the gene map of enzymes which are related to inborn metabolic errors.

Chromosome Mapping↗
PubMed1994

Structure, promoter analysis and chromosomal assignment of the human APEX gene.

APEX nuclease is a mammalian DNA repair enzyme having apurinic/apyrimidinic endonuclease, 3'-5'-exonuclease, DNA 3' repair diesterase and DNA 3'-phosphatase activities. This report describes the organization of the gene (APEX gene) for human APEX nuclease. Human APEX gene was cloned using human APEX cDNA and a human leukocyte genomic library in bacteriophage vector EMBL-3. We proved that human APEX gene consists of 5 exons spanning 2.64 kilobases and suggested that the gene exists as a single copy in the haploid genome. The boundaries between exon and intron follow the GT/AG rule. The major transcription initiation site was assigned by primer extension analysis to C at 515 nucleotides upstream from the ATG initiation codon. The translation initiation and termination sites locate in the exon II and V, respectively. The 5' flanking region (0.89 kilobase) sequenced lacks typical TATA and CAAT boxes, but contains TATA- and CAAT-like sequences and putative cis-acting regulatory elements such as binding sites for Sp1, AP2 and ATF. A part of the 5' flanking region belongs to a CpG island, which extends to the intron II. The CpG island is thought to be a transcription regulatory region of APEX gene, a housekeeping gene. The promoter activity of the 5' upstream region was analyzed by introducing the region in HeLa cells in an expression construct containing luciferase gene as a reporter gene, and the region from position 130 bp upstream to position 205 bp downstream of the major transcription initiation site was shown to be enough for high promoter activity. Northern hybridization experiments suggested that the gene is expressed ubiquitously in human cells. The locus of APEX gene was mapped to human chromosome 14q11.2-q12 using the in situ hybridization technique.

Amino Acid Sequence↗
PubMed1994

Genomic structure and chromosome location of the human mutT homologue gene MTH1 encoding 8-oxo-dGTPase for prevention of A:T to C:G transversion.

8-Oxo-dGTP (8-oxo-7,8-dihydrodeoxyguanosine triphosphate) is produced by active oxygen species in the nucleotide pool of the cell and can be incorporated into cellular DNA. Human cells contain enzyme activity that hydrolyzes 8-oxo-dGTP to 8-oxo-dGMP, thereby preventing occurrence of mutations, caused by misincorporation. When the cDNA for human 8-oxo-dGTPase was expressed in Escherichia coli mutT- mutant cells devoid of self 8-oxo-dGTPase activity, the elevated level of spontaneous A:T to C:G mutation frequency reverted to normal. We isolated the genomic sequence encoding the enzyme and named the gene MTH1 (for mutT human homologue). This gene is composed of at least 4 exons, spans approximately 9 kb, and is located on human chromosome 7p22.

Amino Acid Sequence↗
PubMed1994

The WD gene for Wilson's disease links to the hepatitis of LEC rats.

LEC rats develop an autosomal recessive hepatitis and subsequently liver cancer associated with copper accumulation in the liver similar to that of Wilson's disease. Using 71 backcross [(WKAH x LEC) x LEC] rats, linkage analysis of the hepatitis with the WD gene for Wilson's disease revealed identical segregation and no recombination event between these two genes. This result indicates that the WD gene is a prime candidate for the hts gene responsible for the hepatitis of LEC rats, and suggests that the hepatitis of LEC rats may be caused by a defect in a copper-transporting ATPase expressed in the liver.

Adenosine Triphosphatases↗
PubMed1994

Chromosomal localization of human, rat, and mouse protein phosphatase type 1 beta catalytic subunit genes (PPP1CB) by fluorescence in situ hybridization.

Using fluorescent in situ hybridization (FISH) method, gene encoding the catalytic subunit of protein phosphatase type 1 beta (PPP1CB) in human and its corresponding gene in rat (PP1 delta) and mouse (dis2m2) were mapped to human 2p23, rat 6q21-q23, and mouse 12D, respectively. These results indicate that PPP1CB is a member of conserved syntenic group. It is shown that the genes encoding catalytic subunit of protein phosphatase type 1 family (PP1 alpha, PP1 beta, and PP1 gamma in human and those corresponding genes in rat and mouse), in spite of their high identity, are located to different chromosomes in these three species.

Animals↗
PubMed1994

Molecular phylogenetic status of the iriomote cat Felis iriomotensis, inferred from mitochondrial DNA sequence analysis.

To investigate the molecular phylogenetic status of the Iriomote cat Felis iriomotensis, partial sequences of the mitochondrial 12S rRNA gene (373 bases) and the cytochrome b gene (402 bases) were determined by using the polymerase chain reaction-product direct sequencing technique and then compared with those of seven other feline species. Six Iriomote cats examined in this study showed no intraspecific variation for both genes. The sequence comparisons and the molecular phylogenetic trees indicated that the Iriomote cat is very closely related to the leopard cat Felis bengalensis, which is a widespread species throughout southern and eastern Asia, and that it is reasonable for these two felines to be classified to the same genus. Based on sequence data, the Iriomote cat was estimated to have diverged from the leopard cat arround or less than 0.2 million years ago, and this concurs with the previously reported geological isolation date of the Ryukyu Arc from the Chinese continent. Our results suggest that the geographic barrier has led the fixation of some unique morphological characters into the Iriomote cat population while both the Iriomote cat and the leopard cat still retain very close genetic characters.

Animals↗