| Project/Area Number |
12670732
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Pediatrics
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| Research Institution | TOKYO MEDICAL AND DENTAL UNIVERSITY |
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Principal Investigator |
MORIO Tomohiro Faculty of Medicine, TOKYO MEDICAL AND DENTAL UNIVERSITY, Associate Professor, 医学部・附属病院, 助教授 (30239628)
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| Co-Investigator(Kenkyū-buntansha) |
NONOYAMA Shigeaki Graduate School, TOKYO MEDICAL AND DENTAL UNIVERSITY, Assistant Professor, 医学部・附属病院, 助教授 (40280961)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2001: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Ku70 / 80 / class switch / Fcε receptor / gene regulation / CD95 / IL-4R / CD40 / DNA-PK / IL-4 / CD23 / translocation / IgE |
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| Research Abstract |
Ku70/80 that associates with CD40 translocates into the nucleus when B cells are stimulated through IL-4R/CD40. The same stimulation also leads to maximal expression of low affinity receptor for IgE (CD23). These data suggest that Ku70/80 plays a role in the regulation of CD23 expression. We have generated two different dominant negative (DN) constructs for Ku80 as EGFP-fusion proteins, transfected them into DND-39 B cell line, and examined the effect on IL-4R/CD40-driven CD23 expression. One of the DN constructs that lacks C terminal Ku80 inhibited IL-4R/CD40-driven CD23 expression.
We have employed reporter gene assay to know whether EBVRE functions as enhancer of CD23 expression. Our study has shown that the region encompassing the Ku binding site (EBVRE) shows enhancing effect when B cells were stimulated with IL-4 and anti-CD40. We could not, however, show that Ku70/80 actually occupies the region in EMSA assay. These results suggest that Ku70/80 regulates expression of CD23.
We have started looking at the effect of Ku70/80 on CD40-driven CD95 (Fas) expression and has determined Ku-binding site in the promoter region of CD95.
Another interest is the modification of Ku70/80 and its effect on the Ku70/80function. Our study indicated that stress response leads to degradation of Ku70/80 that is mediated by serine protease or ubiquitination of Ku70/80. We are now examining whether the degradation results in apoptosis of the cells or in cessation of allergic response.
AID is reported to be important for Immunoglobulin class switch. We have sequenced AID from 16 cases of non-X-linked hyper-IgM syndrome and found mutation in 9 cases. We are now examining whether there is any physiological or functional interaction between Ku70/80 and AID.
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