PTEN regulates DNA replication progression and stalled fork recovery

Area of Science:

• Molecular Biology
• Genomics
• Cell Biology

Background:

• Faithful DNA replication is crucial for maintaining genomic integrity.
• PTEN (Phosphatase and Tensin homolog) is a key tumor suppressor involved in genome protection.
• The role of PTEN in DNA replication processes remains incompletely understood.

Purpose of the Study:

• To investigate the role of PTEN in DNA replication.
• To elucidate the mechanism by which PTEN influences replication fork stability and restart.
• To understand the interplay between PTEN and DNA repair proteins at replication forks.

Main Methods:

• PTEN depletion and deletion in cellular models.
• Assessment of replication progression and DNA damage.
• iPOND (in situ proximity-dependent network) analysis to identify protein interactions at replication forks.
• Reactivation assays for stalled replication forks.

Main Results:

• PTEN depletion elevates endogenous replication stress, impairing replication progression and stalled fork recovery.
• Cells lacking PTEN exhibit tolerance to exogenous replication inhibition, accumulating DNA lesions without S phase arrest.
• PTEN physically associates with DNA replication forks and is required for Rad51 recruitment.
• PTEN deletion causes Rad51 dissociation from replication forks, and ectopic PTEN or Rad51 can reactivate stalled forks.

Conclusions:

• PTEN plays a critical role in DNA replication by facilitating the restart of stalled replication forks.
• PTEN's function involves the recruitment and chromatin loading of Rad51.
• Loss of PTEN may trigger a replication stress cascade, potentially contributing to tumorigenesis.