| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2000: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
A glycosyl transferase, Gal NAc T3 is expressed specifically in secretory epithelial glands. And interleukin-13 receptor gene is up-regulated in cisplatin-resistant cells. The nucleotide sequences of promoter regions on these genes are G or C rich. Stem-loop structures consisting of about 60 nucleotides are suggested to be formed in vivo, and play an important role in transcriptional regulation.
A similar stem-loop structure has been found between promoter regions of erythrocyte-type and liver-type pyruvate kinase genes, and their transcription initiation sites are located a distance of only 0.5 kb apart. Formation of stem-loop structure was also confirmed by analysis of reactive thymines under the single strand status to potassium permanganate.
Chromatin structures were analysed by micrococcal nuclease, which cleave preferentially at the linker portion of inactive nucleosomes and within the nucleosome portion of active nucleosomes. As reported previously (SUMMARY OF RESEARCH RESULTS in
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2000), the Gal NAc T-3 and interleukin 13 receptor genes were organized in non-nucleosome structure. Thus, the stem-loop structure(s) located in a boundary between the non-nucleosome region and the surrounding nucleosome region. On the other hand, liver-type pyruvate kinase gene is actively transcrived and erythrocyte-type pyruvate kinase gene is transcriptionally silent in liver cells, whereas the liver-type pyruvate kinase gene promoter were organized in active nucleosomes and erythrocyte-type pyruvate kinase gene promoter showed inactive nucieosome structure. That is, the stem-loop structure in pyruvate kinase genes located in a boundary between inactive nucleosome region and active nucleosome region. Therefore, it has been suggested that these stem-loop structures might function as an insulator element of chromatin structure.
Although a single stem-loop structure consisting about 60 nucleotides was initially supposed, similar stem-loop structures seemed to be scattered in these promoter regions. Therefore, at first the determination of boundaries of the regions laden with stem-loop structures should be performed. Secondly, the functional identification as an insulator element of chromatin sturucture should be done in the near future. Less
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