2007 Fiscal Year Final Research Report Summary
Analysis of the amplification promoting sequence (EXP) in the ribosomal RNA gene
| Project/Area Number |
17370065
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Molecular biology
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| Research Institution | National Institute of Genetics (2006-2007)
National Institute for Basic Biology (2005) |
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Principal Investigator |
KOBAYASHI Takehiko National Institute of Genetics, Department of Cell Genetics, Professor (40270475)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Genome instability / Ribosomal RNA gene repeats(rDNA) / Gene amplification / Non coding RNA / DNA recombination / Cohesin / Phylogenetic footprinting / Cellular senescence |
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| Research Abstract |
The ribosomal RNA gene repeats (rDNA) is one of the most characteristic regions in eukaryotic chromosomes. The repeats consist of more than 100 tandem units occupying large part of the chromosome in most of organisms. Repeated genes families such as the ribosomal RNA genes (rDNA) are thought to be fragile sites for deletional recombination. However, as for the rDNA, cells have gene amplification system and recover copy number to the wild type level. We found a cis-essential sequence (EXP) for the amplification. In this research, I analyzed molecular mechanism of the EXP.
First, we did the phylogenetic footprinting assay in the EXP using several kinds of yeasts and found a conserved region. Interestingly, the region was a bi-directional noncoding transcriptional promoter that is reported〜20 years ago. We tested the character of the promoter and found the transcription was essential for the amplification. Interestingly, when the rDNA copy number reduces, the transcription is activated and it removes cohesin from the region. As the result, unequal sister-chromatid recombination increases and amplification is induced. Then, when the copy number reaches around the wild type level, Sir2 protein represses the transcription and by the function of recovered cohesin the unequal sister-chromatid recombination is restricted. Like these, we found the copy number regulation system, that is, Sir2 regulates rDNA copy number through E-pro transcription by changing cohesin association.
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Research Products
(83 results)
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[Journal Article] Abnormality in initiation program of DNA replication is monitored by the highly repetitive rRNA gene array on chromosome XII in budding yeast.2007
Author(s)
Ide, S., Watanabe, K., Watanabe, H., Shirahige, K., Kobayashi. T., Maki, H.
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Journal Title
Mol Cell Biol 27
Pages: 568-578
Description
「研究成果報告書概要(欧文)」より
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