The RBBP6/ZBTB38/MCM10 Axis Regulates DNA Replication and Common Fragile Site Stability

• The mammalian E3 ubiquitin ligase RBBP6 prevents spontaneous DNA damage
• RBBP6 prevents DNA damage by destabilizing the transcriptional repressor ZBTB38
• When ZBTB38 is overabundant, DNA replication is slower and fragile sites are lost
• ZBTB38 regulates replication efficiency by controlling MCM10 transcription

SummaryFaithful DNA replication is essential for the maintenance of genome integrity. Incomplete genome replication leads to DNA breaks and chromosomal rearrangements, which are causal factors in cancer and other human diseases. Despite their importance, the molecular mechanisms that control human genome stability are incompletely understood. Here, we report a pathway that is required for human genome replication and stability. This pathway has three components: an E3 ubiquitin ligase, a transcriptional repressor, and a replication protein. The E3 ubiquitin ligase RBBP6 ubiquitinates and destabilizes the transcriptional repressor ZBTB38. This repressor negatively regulates transcription and levels of the MCM10 replication factor on chromatin. Cells lacking RBBP6 experience reduced replication fork progression and increased damage at common fragile sites due to ZBTB38 accumulation and MCM10 downregulation. Our results uncover a pathway that ensures genome-wide DNA replication and chromosomal stability.

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