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Purification of Ubiquitinated p53 Proteins from Mammalian Cells
Published on: March 21, 2022
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Context-Dependent Function of Long Noncoding RNA PURPL in Transcriptome Regulation during p53 Activation.
Corrine Corrina R Hartford1, Roshan L Shrestha2, Lorinc Pongor3
1Regulatory RNAs and Cancer Section, Genetics Branch, Center for Cancer Research (CCR), National Cancer Institutegrid.48336.3a (NCI), National Institutes of Healthgrid.94365.3d (NIH), Bethesda, Maryland, USA.
Molecular and Cellular Biology
|November 7, 2022
Summary
The long non-coding RNA PURPL fine-tunes mitotic gene expression upon p53 activation in liver cancer. Depleting PURPL significantly alters gene expression and reduces mitotic cells, revealing its context-dependent role in cell cycle arrest.
Area of Science:
- Molecular Biology
- Cancer Research
- Genomics
Background:
- The p53-induced long non-coding RNA (lncRNA) PURPL is known to suppress basal p53 levels.
- PURPL exhibits significantly higher expression in liver cancer cells compared to other cell types.
Purpose of the Study:
- To investigate the function of PURPL upon p53 activation in liver cancer.
- To identify novel PURPL transcripts and elucidate its role in regulating gene expression and cell cycle.
Main Methods:
- Isoform sequencing to discover novel PURPL transcripts.
- CRISPR interference (CRISPRi) to deplete PURPL.
- RNA-sequencing (RNA-Seq) and Nutlin treatment to induce p53.
- Pathway analysis and cell cycle analysis.
Main Results:
- Discovery of novel PURPL transcripts with retained introns and/or unannotated exons.
- Loss of PURPL altered only 7 genes in untreated cells but ~800 genes upon p53 activation, indicating context-dependent function.
- PURPL depletion significantly decreased the percentage of mitotic cells and pathway analysis implicated PURPL in fine-tuning mitotic gene expression.
Conclusions:
- Novel PURPL transcripts have been identified.
- PURPL plays a critical role in moderating the expression of mitotic genes during p53 activation.
- PURPL is essential for controlling cell cycle arrest in response to p53 signaling in liver cancer.
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