| Gene name: | ASXL1 |
| Aging type: | Prevent |
| Aging characteristic: |
| Tissue type: | -- |
| Cell name: | MEF |
| Experiment: | SA-β-gal activity assay//DAPI staining//SAHF//Cell morphological analysis//Western blot//Microarray//qRT-PCR |
| Description: | SA-β-gal staining was significantly greater in two different passages of Asxl1-null MEFs than in WT MEFs. Consistently, more SAHF were formed in Asxl1-null MEFs as determined by DAPI staining.More senescence was induced at passage 6 of Asxl1-null MEFs because of growth retardation in the later stages. In addition, Asxl1-deleted MEFs displayed an enlarged and flattened shape (data not shown).Notably,the up-regulation of another Cdk inhibitor, p16Ink4a (a hallmark of cellular senescence),was observed in Asxl1-null cells, whereas p21Waf1 was down-regulated at the protein and RNA levels.In addition to p16Ink4a, other senescence -associated genes such as p57Kip2, Mmp1, and Pai1 were also up-regulated as shown by microarray analysis and RT-qPCR. |
| Target gene: | E2F//EZH2 |
| Official symbol(s): | E2F1//EZH2 |
| R-AG-Target gene: | --//-- |
| Subcategory: | Unclear |
| Target gene experiment: | qRT-PCR//Co-IP |
| Target gene description: | Most of the E2F target genes were significantly down-regulated in Asxl1-null.To explore the link between ASXL1 and EZH2,we first measured the physical interaction by co-IP analysis. As reported previously, Flag-EZH2 interacts with endogenous ASXL1. |
| Regulatory pathway: | AKT-E2F |
| R-AG-Pathway: | -- |
| Official symbol(s): | AKT1-E2F1 |
| Pathway experiment: | Western blot//CHIP |
| Pathway description: | A significant decrease in p27Kip1 phosphorylation was observed in Asxl1-null MEFs, which was likely due to Akt inactivation. As shown by IP assays using HEK293 cells treated with IGF-1, we demonstrated that p27Kip1 interacts with both ASXL1 and AKT1 regardless of IGF-1–induced AKT phosphorylation. Consistent with reports shown above, IGF-1 treatment induced the cytoplasmic export of p27Kip1 in normal MEFs, whereas the IGF-1 effect was abolished in Asxl1-null MEFs; p27Kip1 was thus retained in the nucleus. Consequently, we observed a gradual down-regulation of Rb phosphorylation, but no change in the Rb level, during culture of Asxl1-null MEFs. In response to IGF-1, no effect of Asxl1 was observed on E2F1 binding to the Ccna2 promoter, while the IGF-1–repressed Rb binding was recovered in Asxl1-null MEFs after Rb activation. |
Annotation:
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