| Project/Area Number |
08044279
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KONDOH Shigeru Kyoto University Dept. Of Medical Chemistry. Instructor, 大学院・医学研究科, 講師 (10252503)
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| Co-Investigator(Kenkyū-buntansha) |
COHN Melvin California University. The Salk Institute. Professor, ソーク研, 教授
HONJO Tasuke Kyoto University Dept. Of Medical Chemistry. Instructor, 大学院・医学研究科, 教授 (80090504)
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| Project Period (FY) |
1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1996: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Immunoglobulin / Isotype / Switch / PCR / DNA / CH12 / Recombination / S-region / 抗体 / 遺伝子 / 組み換え / B細胞 |
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| Research Abstract |
Immunoglobulin (Ig) heavy chain class switch recombination occurs mainly by joining two switch (S) regions, segments of tandemly repeated DNA sequences that lie upstream of heavy chain constant region genes. The products of this recombination event are a chromosomal DNA joint and a 'Looped-out' circular DNA joint. Although a previous study showed that 40% of chromosomal joints in the μgene switch region (Sμ) are found in the flanking regions of Sμ, which do not contain typical Sμ region repeats, other studies revealed that almost all recombination sites on looped-out circular DNA are found within S regions. To resolve this discrepancy, we have isolated and sequenced 164 DNA fragments containing recombination joints from both chromosomal and looped-out DNA of a single cell line, the murine B lymphoma line CH12F3, which switches from IgM to IgA production with a high frequency upon cytokine simulation. The recombination sites were distributed almost evenly in the Sμ region and its flanking regions, suggesting that the final joining of DNA ends may not necessarily take place in S regions. In contrast, there were few joining sites in the exon located 5' of the switch region (the Iμ exon), suggesting that the 3' end of the Iμ exon might be the upstream border of the recombination joint.
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