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Updated: Jun 5, 2026

Purification of Ubiquitinated p53 Proteins from Mammalian Cells
Published on: March 21, 2022
Usp7 and Uhrf1 control ubiquitination and stability of the maintenance DNA methyltransferase Dnmt1
Weihua Qin1, Heinrich Leonhardt, Fabio Spada
1Department of Biology II, Ludwig Maximilians University Munich, Planegg-Martinsried, Germany.
Abstract:
In mammals Dnmt1 is the DNA methyltransferase chiefly responsible for maintaining genomic methylation patterns through DNA replication cycles, but how its maintenance activity is controlled is still not well understood. Interestingly, Uhrf1, a crucial cofactor for maintenance of DNA methylation by Dnmt1, is endowed with E3 ubiquitin ligase activity. Here, we show that both Dnmt1 and Uhrf1 coprecipitate with ubiquitin specific peptidase 7 (Usp7), a de-ubiquitinating enzyme. Overexpression of Uhrf1 and Usp7 resulted in opposite changes in the ubiquitination status and stability of Dnmt1. Our findings suggest that, by balancing Dnmt1 ubiquitination, Usp7 and Uhrf1 fine tune Dnmt1 stability.
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