2004 Fiscal Year Final Research Report Summary
Targeted disruption of the MARs in the human imprinted genes cluster
| Project/Area Number |
15510159
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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 |
基礎ゲノム科学
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| Research Institution | National University Corporation Tottori University |
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Principal Investigator |
KUGOH Hiroyuki National University Corporation Tottori University, Graduate School of Medical Science, Associate Professor, 医学系研究科, 助教授 (40225131)
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| Project Period (FY) |
2003 – 2004
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| Keywords | imprinted genes / LIT1 / IGF2 / microcell fusion / MAR / FISH / noncoding RNA / chromatin |
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| Research Abstract |
In mammals, most imprinted genes are clustered into large genomic domains and often share common regulatory elements. Regulation of gene expression is thought to be a multistep process involving changes in chromatin structure by site-specific events such as the methylation or the acethylation on DNA and histones. Matrix attachment regions(MARs) are DNA elements for the genome that attach to the nuclear matrix. MARs are located in the intron of several large genes and also act as the borders of transcription unit, suggesting that MARs play a role in modulating transcription of the genes under the chromatin domain. It may contribute to a factor that control long-range epigenetic effects on a megabase scale such as genomic imprinting.
To demonstrate this hypothesis, we investigated the function of MARs in imprinted domain. Here we created modified human chromosome carrying the targeted deletion of MARs in IGF2 and LIT1 on human chromosome 11p15.5 using recombination-proficient chicken DT40 cells. Furthermore, we transferred the modified human chromosome into chinese hamster ovary(CHO) cells to analyze the effect of the targeted alterations at this imprinted cluster.
The imprinted noncoding RNA LIT1, a product of the KCNQ1OT1, is involved in cis-limited silencing within an imprinted cluster on human chromosome 11p15.5. Although the locus serves as an imprinting center (IC), the function of the LIT1 gene product is unclear. In this study, RNA in situ hybridization provides evidence suggesting that the LIT1 RNA stably localizes to the LIT1 region and plays an important role in transcriptional silencing of the imprinting domain.
Thus, it will be important to focus future study on the interactions between chromatin and the nuclear matrix in order to better understand new epigenetic gene regulation, including imprinted genes.
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