N. Shindo-Okada

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The guanine insertion enzyme isolated from Escherichia coli (tRNA transglycosylase) catalyzed the incorporation of bases of Q (queuosine) precursors into E. coli undermodified tRNAAsn and tRNATyr. These bases of Q precursors were inserted in the first position of the anticodon of tRNASn and tRNATyr, replacing guanine originally located in that position.(More)
To identify genes differentially expressed in association with metastatic potential of K-1735 mouse melanoma cells, the mRNA differential display method was applied to compare mRNAs from high- and low-metastatic K-1735 cells. A novel gene was identified as being expressed in high-metastatic cells but not in low-metastatic cells. Sequence analysis revealed(More)
We previously isolated a partial cDNA fragment of a novel gene, Elm1 (expressed in low-metastatic cells), that is expressed in low-metastatic but not in high-metastatic K-1735 mouse melanoma cells. Here we determined the full-length cDNA structure of Elm1 and investigated the effect of Elm1 expression on growth and metastatic potential of K-1735 cells. The(More)
Azatyrosine [L-beta-(5-hydroxy-2-pyridyl)-alanine], an antibiotic isolated from Streptomyces chibanensis, inhibited the growth of NIH 3T3 cells transformed by the activated human c-Ha-ras gene but did not significantly inhibit the growth of normal NIH 3T3 cells. Surprisingly, upon treatment with azatyrosine most of the transformed cells apparently became(More)
To identify genes differentially expressed in association with the metastatic potential of K-1735 mouse melanoma cells, the mRNA differential display method was applied to compare mRNAs from high- and low-metastatic K-1735-derived cells. Three of the high- and three of the low-metastatic clones were used to reduce the false positives in the initial(More)
A single painting of 7,12-dimethylbenz[a]anthracene on the skin of transgenic mice harboring the human protooncogene c-Ha-ras induced papillomas at 100% incidence after 20 weeks (M. Izawa et al., unpublished data). Application of L-beta-(5-hydroxy-2-pyridyl)alanine (azatyrosine) to the skin at a dose of 2 mg/mouse once every 3 days after initiation with(More)
We previously reported that mouse NIH 3T3 cells transformed by transfection of activated human c-Ha-ras become apparently normal upon treatment with the antibiotic azatyrosine. The revertant cells maintain their normal phenotype during prolonged culture in the absence of azatyrosine, although activated p21ras is still expressed. The normal phenotype induced(More)
The guanine insertion enzyme from Escherichia coli catalyzes exchange of guanine located at the first position of the anticodon of tRNA with radioactive guanine (N. Okada and S. Nishimura, unpublished data). tRNA isolated from various tumors, including slowly growing Morris hepatoma 7794A, incorporated considerable guanine with E. coli guanine insertion(More)
The amounts of hypo-modified tRNAs having guanine in place of queuine in murine erythroleukemic cells decreased markedly when the cells differentiated into mature erythroid cells. The amounts of these hypo-modified tRNAs can be determined easily by measuring incorporation of labeled guanine into tRNA with Escherichia coli tRNA--guanine transglycosylase. The(More)
Transfer ribonucleic acid (tRNA) guanine transglycosylase (guanine insertion enzyme) was isolated from rat liver and extensively purified. The enzyme catalyzes an exchange of queuine (the base of queuosine, Q) as well as its precursors and guanine for guanine originally located in the first position of the anticodon of "undermodified" tRNATyr, tRNAHis,(More)