Researchers Identified POLD3 Function in DNA Synthesis
The study clarifies how the POLD3 subunit coordinates DNA strand replication during mitosis.
Updated on Sept. 19, 2026 in Life Sciences
Researchers have identified that the POLD3 subunit of DNA polymerase delta is essential for coordinating DNA synthesis during mitosis. This research, published on September 19, 2026, highlights how this process functions within a variant of Break-Induced Replication.
Why it matters
Understanding the function of POLD3 in mitosis provides new insights into how cancer cells manage oncogene-induced replication stress. This knowledge may eventually support the development of therapies that target specific DNA replication pathways.
Experiments using HeLa clones with mutations in the PCNA-interacting domain of POLD3 demonstrate that while S-phase replication remains intact, lagging strand synthesis fails during MiDAS. This confirms POLD3 interacts with PCNA to enable DNA synthesis when cells undergo mitotic replication.
The players
POLD3
The third subunit of DNA polymerase delta that facilitates coordination during mitotic DNA synthesis.
HeLa cells
An immortal cell line used as an experimental model to study replication stress and DNA repair pathways.
The details
MiDAS, or Mitotic DNA Synthesis, is a specialized process that completes DNA replication during the mitotic phase of the cell cycle. Researchers mapped newly replicated DNA at these sites using high-resolution techniques to observe how the POLD3 subunit coordinates both leading and lagging DNA strands. The mechanism relies on the interaction between POLD3 and PCNA, a protein that acts as a sliding clamp for DNA polymerase, ensuring stability during the replication of complex genetic material.
Timeline
September 19, 2026: The research findings were published.
The Tech Race
This research builds upon established work in Break-Induced Replication (BIR) by isolating the specific role of the POLD3 subunit during mitosis. It situates the study within ongoing efforts to decode how cancer cells bypass replication stress to maintain genomic stability.
This discovery identifies a potential biological target for future cancer treatments rather than an immediately available technology. Researchers and drug developers will likely use these findings to screen for compounds that disrupt the POLD3-PCNA interaction.
The takeaway
The study confirms that POLD3 is critical for navigating DNA replication stress during mitosis. Future research should watch for potential therapeutic candidates that inhibit POLD3-mediated pathways in high-stress cancer cells.
Further reading
For more research on replication mechanisms, visit the Life Sciences section.
Source note: This article includes information reported by Nature.
