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Y Kameoka

Publications and source records attributed to Y Kameoka.

7 recordsLinked to original sources
PubMed1992

A quantitative analysis of radiation-induced chromosome aberrations with a fluorescent digital image microscope.

Using a synthetic, alpha satellite consensus DNA unit as a probe, we could show dicentrics as well as acentric fragmented chromosomes in metaphases of gamma-irradiated lymphocyte cells and that the number of appearance of dicentrics or acentric fragments seemed to be proportional to radiation doses. To make such examination with a large number of chromosomes of metaphases, a quantitative fluorescence measurement was performed using a fluorescent microscope digital image analysis system. The relative amounts of fluoresceinated probe hybridized to alpha satellite DNA varied with chromosomes to a certain extent (1-4% of total probe-fluorescence of one metaphase). However, we could score dicentrics and acentric fragments as dots with extraordinarily higher or low percentage in plots of relative amount of probe-fluorescence on metaphase chromosome in gamma-irradiated cells. The number of appearance of acentric fragments were proportional to radiation doses of 1, 2 and 4 Gy. In the case of dicentrics, the number of appearance seemed to be proportional to square doses. Further, to reduce the variation of relative amounts of probe-fluorescence, we tried to make probe-fluorescence reflect the content of alpha satellite DNA on each chromosome more exactly, using a DNA probe amplified by polymerase chain reaction.

Chromosome Aberrations↗
PubMed1990

Application of synthetic DNA probes of human alpha satellite consensus monomer for detection of centromere-involved chromosome abnormalities.

We have synthesized the alphoid monomer of 171 bp based on the consensus sequence of human alpha satellite DNA and constructed a clone of dimeric or tetrameric sequence unit. Southern blot analysis using the clone as a probe showed restriction site periodicities in human DNA digested by EcoRI or BamHI. The synthetic consensus unit could detect the alpha repeated centromeric regions of all human chromosomes by fluorescence in situ hybridization. Using the cells having a dicentric X chromosome, we showed that the two centromeric regions were stained with fluorescent alpha satellite DNA probes. Thus the probe would be useful to detect chromosomal abnormalities such as dicentrics.

Base Sequence↗
PubMed1990

Over 80% of NotI sites are associated with CpG rich islands in the sequenced human DNA.

Clones containing DNA segments linked to NotI sites are not only useful for ordering the NotI fragments fractionated by pulsed field gel, but also valuable in the search of unknown genes, because they often contain the CpG rich islands and genes related with them. To know the probability of association of NotI sites with CpG rich islands, we screened 5,188 sequences accumulated in DNA data base for the presence of NotI site and examined the distribution of CpGs around them. The sequential calculation of G + C content and frequency of CpG occurrence at each nucleotide position identified the CpG rich domains close to NotI sites in 77 sequences, which corresponds to 84% of total number of candidate sequences. This frequency is consistent well with the prediction that 89% of NotI sites in mammalian genome are likely to be present in CpG rich islands and would stress the importance of cloning of NotI linking sequences for direct isolation of desired genes. Furthermore, 63 islands newly identified in this study should provide a clue for understanding the transcriptional regulation of associated genes.

Base Sequence↗
PubMed1989

Comparative restriction endonuclease analysis of varicella-zoster virus clinical isolates.

The DNAs of 67 isolates of varicella-zoster virus (VZV) obtained from 31 individuals were compared by restriction endonuclease analysis using BamHI, EcoRI, PstI and SmaI. All of the epidemiologically unrelated 26 isolates could be differentiated using SmaI and another one or two enzymes. However, the DNA cleavage profiles of multiple VZV isolates from the same patient and the isolates from a group of patients who were infected with VZV from the same source were found to be identical to each other, as reported previously. No patients were found who were simultaneously infected with different VZV strains. Moreover, VZV showed no change in DNA fragment profiles after serial passages not only through human embryonic lung cells but also through patients.

Adult↗
PubMed1988

A cell cycle G0-ts mutant, tsJT60, becomes lethal at the nonpermissive temperature after transformation with adenovirus 12 E1B 19K mutant.

tsJT60, a temperature-sensitive (ts) cell-cycle mutant of Fischer rats, is viable at both the permissive (34 degrees C) and nonpermissive (40 degrees C) temperatures. The cells grow normally in exponential growth phase at both temperatures, but when stimulated with serum from G0 phase they enter S phase at 34 degrees C but not at 40 degrees C. tsJT60 cells transformed with human adenovirus (Ad) 12 dl205, which lacks the E1B 19-kDa polypeptide gene, were lethal at 40 degrees C, whereas tsJT60 cells transformed with Ad12 wt, dl207, which lacks E1B 58-kDa protein gene, or in206B, which produces 19- to 58- kDa fused protein, were viable. Degradation of cell DNA occurred in dl205-transformed tsJT60 cultured at both 34 degrees C and 40 degrees C. Neither cytocidal phenotype nor degradation of DNA occurred in 3Y1 cells (a parental line of tsJT60) transformed with dl205. These results suggest that the lethal phenotype and degradation of DNA are related to the ts mutation in tsJT60 and also to the lack of Ad12 E1B 19kDa polypeptide.

Adenoviridae↗