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Chromosome segregation and RNAi in vertebrate cells
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| Nature Cell Biology 11 July 2004 |
| Fukagawa Laboratory, Division of Molecular Genetics |
Dicer is essential for formation of heterochromatin structure in vertebrate cells.
Fukagawa T, Nogami M, Yoshikawa M, Ikeno M, Okazaki T, Takami Y, Nakayama T, Oshimura M.
Nature Cell Biology, DOI: 10.1038/ncb1155, (2004)
RNA interference (RNAi) is an evolutionarily conserved gene-silencing pathway in which the nuclease Dicer cleaves double-stranded RNA into smaller interfering RNAs. To examine the biological function of the RNAi-related pathway in vertebrate cells, we generated a conditional loss-of-function mutant of Dicer in a chicken-human hybrid DT40 cell line that contains human chromosome 21. Loss of Dicer leads to cell death with accumulation of abnormal mitotic cells that show premature sister chromatid separation. Aberrant accumulation of transcripts from α-satellite sequences, which consist of human centromeric repeat DNAs, was detected in Dicer-deficient cells. Immunocytochemical analysis revealed abnormalities in localization of heterochromatin proteins, Rad21 cohesin protein, and BubR1 checkpoint protein, but localization of core kinetochore proteins such as CENP-A and -C was normal. We conclude that Dicer-related RNAi machinery is involved in formation of the heterochromatin structure in higher vertebrate cells.
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FISH analysis revealed aberrant chromosomes in which the sister chromatids were separated. FISH analysis was performed with a human chromosome 21 centromere-specific probe (green). We observed a significant increase in the distance between the sister centromeres, indicating that the sister chromatids in Dicer-deficient cells were separated significantly.
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Entrez PubMed |
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