Structural Stability of DNA During Cell Division

Scientists have long believed that DNA reconstructs its complex structure after cell division, which is vital for regulating gene activity within cells. However, recent research from the Massachusetts Institute of Technology reveals that this conventional model is not entirely accurate. Using high-resolution genome mapping techniques, the team discovered that small three-dimensional loops remain intact even during cell division.

Structural Stability of DNA During Cell Division

Cell divisions have traditionally been considered a phase where cells lose their genetic structure, but the new study suggests there is a continuous structure during division. The small three-dimensional loops, which connect regulatory DNA elements and genes, remain intact and even strengthen as chromosomes condense in preparation for division. This discovery helps explain how cells retain their genetic memory and re-establish genetic interactions after division.

Researchers found that these loops actually strengthen during chromosome condensation, bringing distant regulatory elements closer together and encouraging their adhesion. This discovery could allow cells to “remember” the genetic interactions that existed before division and restore them afterward.

Using New Techniques to Understand Genetic Structure

Over the past two decades, scientists have discovered that DNA in the cell nucleus organizes itself into three-dimensional loops. Many of these loops allow genes to interact with distant regulatory regions, while others form during division to tightly pack chromosomes. Most of these maps relied on the Hi-C technique, but this method lacks the precision needed to detect fine interactions between genes and regulatory sequences known as enhancers.

In 2023, the research team developed a new technique called Region-Capture Micro-C (RC-MC), which allows for the creation of highly detailed three-dimensional maps of targeted genome regions. Using this technique, they discovered a new structural feature they called “microcompartments,” which are densely connected small loops formed when adjacent enhancers and promoters converge.

Understanding Genetic Activity During Division

The new discovery may also explain the increased genetic activity that has long been observed at the end of division. Although scientists believed that genetic transcription completely stops during division, recent studies have shown a temporary increase in genetic activity before it halts again.

The MIT team found that the loops forming the microcompartments are more likely to be near genes that experience increased activity during division. They also discovered that these loops form as a result of genome condensation occurring during division.

Conclusion

This study illustrates how cells can use structural memory to maintain their genetic activity across cell divisions. The findings suggest that the genetic environment is not entirely void during division but contains fine structures that may play a role in regulating genetic activity. As researchers continue to explore how these structures might be affected by changes in cell shape and size, this study offers new insights into how genetic integrity is preserved across cellular generations.