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| Status |
Public on Mar 25, 2020 |
| Title |
Nuclear aconitase regulates heterochromatin formation by interacting with Chp1 |
| Organism |
Schizosaccharomyces pombe |
| Experiment type |
Expression profiling by high throughput sequencing
Genome binding/occupancy profiling by high throughput sequencing
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| Summary |
Aconitase is a highly conserved metabolic enzyme for TCA cycle. In Schizosaccharomyces pombe, an aconitase (Aco2) is localized in both mitochondria and the nucleus, apart from an exclusively mitochondrial one (Aco1). We investigated the role of nuclear Aco2, and present evidences that it interacts with Chp1, a heterochromatin-associated HP1 protein, and acts as an anti-silencing factor. Nuclear depletion of Aco2 by deleting nuclear localization signal (aco2ΔNLS) suppressed the gene-silencing defects of RNAi mutants Δago1 and Δdcr1 at the centromere, where RNAi-mediated heterochromatin formation prevails. The aco2 mutation caused an increase in Chp1 binding to the centromeric repeats, with concomitant increase in the level of dimethylated histone H3K9, reflecting restoration of heterochromatin formation. Co-precipitation revealed that Aco2 interacted directly with Chp1 via the N-terminal region (1-235 aa), where the chromodomain (20-75 aa) that recognizes methylated H3K9 is located. Genome-wide analysis revealed that the aco2ΔNLS mutation caused elevation in the level of H3K9me2 not only at heterochromatic but also at euchromatic regions in the Δago1 mutant background. We also found that the single aco2ΔNLS mutation caused aberrant gene silencing at sub-telomeric and some euchromatic coding genes. These results demonstrate that Aco2 inhibits heterochromatin assembly over a wide range, by interfering with Chp1. Its contribution is prominent in the RNAi-independent heterochromatic region or in the absence of RNAi effector complex RITS that holds Chp1. Taken together, this work shows a clear example of a metabolic enzyme that can function in the nucleus as an epigenetic modulator of gene expression.
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| Overall design |
For ChIP-seq experiment (S. pombe): Genome-wide distributions of H3K9me2 in wild-type, aoc2∆N, and ago1∆ x aco2∆N cells. Genome-wide distributions of Chp1 in wild-type cells. For RNA-seq experiment: Strand-specific mRNA-Seq of wild type and aoc2∆N cells
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| Contributor(s) |
Jung S, Choi Y, Lee D, Roe J |
| Citation(s) |
31255284 |
| |
| Submission date |
Jul 24, 2017 |
| Last update date |
Mar 25, 2020 |
| Contact name |
Yoonjung Choi |
| E-mail(s) |
jjungii@kaist.ac.kr
|
| Organization name |
KAIST
|
| Street address |
291 Daehak-ro, Yuseong-gu
|
| City |
Daejeon |
| ZIP/Postal code |
34141 |
| Country |
South Korea |
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| Platforms (1) |
| GPL17225 |
Illumina HiSeq 2500 (Schizosaccharomyces pombe) |
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| Samples (15)
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| Relations |
| BioProject |
PRJNA395555 |
| SRA |
SRP113458 |
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