2000 Fiscal Year Final Research Report Summary
Analysis of Intranuclear Communication of Homologous Alleles of Imprinted Genes and Transgenes
| Project/Area Number |
11660086
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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 |
応用微生物学・応用生物化学
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| Research Institution | Mie University |
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Principal Investigator |
OKUMURA Katsuzumi Mie University, Faculty of Bioresources, Associate Professor, 生物資源学部, 助教授 (30177183)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Genomic imprinting / FISH / DNA methylation / Histone acetylation / Nuclear matrix / Heterochromatin |
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| Research Abstract |
Investigations of imprinted regions provide clues that increase our understanding of the regulation of gene functions at higher order chromosomal domains. The relative positions of the chromosome 15 centromere and the imprinted SNRPN gene in interphase nuclei of human myeloid leukemia HL60 cells were compared by multicolor FISH, because the homologous association of this imprinted chromosomal domain was previously observed in lymphocytes and lymphoblasts. Preferential association of SNRPN interhomologues does not occur during the cell cycle, although this gene exhibited asynchronous replication and monoallelic expression. SNRPN was found to localize at the periphery of the chromosome territories, and it preferentially faces the nuclear membrane. The SNRPN gene and the centromere are located close to each other late in S phase, reflecting that these DNA segments may be compacted into the same intranuclear subcompartments with the progress of S phase. Our results suggest that the charact
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eristic of mutual recognition of imprinted regions is determined by certain cellular regulation, and it is not necessary for the allele-specific features of an imprinted gene. We have adapted a FISH method to detect nascent RNA molecules of the imprinted SNRPN gene at the initial transcription sites in nuclei of human HL60 and WI38 cells. Simultaneous detection of RNA and DNA of SNRPN by FISH using the cosmid probe confirmed its monoallelic expression in these cell lines. Treatment of both cells by inhibitors of DNA methylation and histone deacetylation resulted in time-dependent increase of the cell population with the biallelic expression of SNRPN.We investigated the allele-specific gene silencing of imprinted regions by their association with heterochromatin. Our results suggested the possibility and dependency on DNA replication. We further examined the relationship between gene expression and nuclear matrix by using imprinted genes, suggesting that the expressed allele associated with the nuclear matrix. Less
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