p53 pathway is involved in cell competition during mouse embryogenesis

Area of Science:

• Cellular biology
• Tumor suppressor function
• Developmental biology

Background:

• The tumor suppressor p53 is activated by acute stress, inducing cell cycle arrest or apoptosis.
• The in vivo response to mild p53 activation from low-level stress is not well understood.
• Murine double minute (MDM)2 and MDM4 are key negative regulators of p53.

Purpose of the Study:

• To investigate the in vivo consequences of mild p53 activation.
• To explore the role of p53 in cellular fitness and competition under low-level stress.

Main Methods:

• Utilized Mdm2 and Mdm4 haploinsufficiency to induce mild p53 activation in mice.
• Generated genetic mosaic embryos containing both Mdm2+/-Mdm4+/- cells and wild-type cells.
• Analyzed cellular growth, competition, and p53 levels during development.

Main Results:

• Mdm2+/-Mdm4+/- mice showed normal embryogenesis, but their cells exhibited a growth disadvantage.
• Cells with mild p53 activation were outcompeted by wild-type cells in mosaic embryos.
• This out-competition phenotype was dependent on p53 levels.

Conclusions:

• Mild p53 activation leads to reduced cellular fitness and altered cell fates in a competitive environment.
• The findings reveal a role for p53 in cell competition, similar to phenomena observed in Drosophila.
• p53 may function to eliminate unfit cells, thereby ensuring overall organ and animal fitness.