SIRT1 stabilizes extrachromosomal gene amplification and contributes to repeat-induced gene silencing
| Autor: | Bhushan Thakur, Kazuho Ishine, Noriaki Shimizu, Mirit I. Aladjem, Ryonosuke Taniguchi, Koichi Utani |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
gene amplification RIGS repeat-induced gene silencing FISH fluorescence in situ hybridization extrachromosomal element HDAC histone deacetylase BFB breakage-fusion-bridge Biology Biochemistry Genomic Instability sirtuin1 03 medical and health sciences Gene Knockout Techniques SIRT1 Sirtuin 1 Sirtuin 1 DM double minute Extrachromosomal DNA Cell Line Tumor Gene duplication Gene expression Gene silencing Humans Gene Silencing Scaffold/matrix attachment region Molecular Biology Gene protein expression MAR matrix attachment region Reporter gene 030102 biochemistry & molecular biology HSR homogeneously staining region DSB double strand breakage Cell Biology Amplicon repeat-induced gene silencing Cell biology 030104 developmental biology histone deacetylase gene expression d2EGFP destabilized enhanced GFP biological phenomena cell phenomena and immunity DIG digoxigenin hormones hormone substitutes and hormone antagonists Research Article |
| Zdroj: | The Journal of Biological Chemistry |
| ISSN: | 1083-351X |
| Popis: | Sirtuin 1 (SIRT1) is a protein deacetylase that maintains genome stability by preventing the activation of latent replication origins. Amplified genes in cancer cells localize on either extrachromosomal double minutes (DMs) or the chromosomal homogeneously staining region. Previously, we found that a plasmid with a mammalian replication initiation region and a matrix attachment region spontaneously mimics gene amplification in cultured animal cells and efficiently generates DMs and/or an homogeneously staining region. Here, we addressed the possibility that SIRT1 might be involved in initiation region/matrix attachment region–mediated gene amplification using SIRT1-knockout human COLO 320DM cells. Consequently, we found that extrachromosomal amplification was infrequent in SIRT1-deficient cells, suggesting that DNA breakage caused by latent origin activation prevented the formation of stable extrachromosomal amplicons. Moreover, we serendipitously found that reporter gene expression from the amplified repeats, which is commonly silenced by repeat-induced gene silencing (RIGS) in SIRT1-proficient cells, was strikingly higher in SIRT1-deficient cells, especially in the culture treated with the histone deacetylase inhibitor butyrate. Compared with the SIRT1-proficient cells, the gene expression per copy was up to thousand-fold higher in the sorter-isolated highest 10% cells among the SIRT1-deficient cells. These observations suggest that SIRT1 depletion alleviates RIGS. Thus, SIRT1 may stabilize extrachromosomal amplicons and facilitate RIGS. This result could have implications in cancer malignancy and protein expression. |
| Databáze: | OpenAIRE |
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