Researchers have discovered a new approach to examining changes in the DNA replication process in laboratory conditions, utilizing genetically modified yeast. This innovative method provides a clearer perspective compared to existing drug-based techniques used to investigate cell cycle arrest, an essential mechanism for addressing cancer and genetic disorders.
Researchers at Colorado State University have discovered a new method to examine changes during the DNA replication process in lab environments by using genetically modified yeast. This approach offers a clearer perspective compared to current drug-based techniques employed to explore cell cycle arrest, which is a crucial mechanism for treating cancer and genetic disorders.
The results of this research were shared in the Proceedings of the National Academy of Sciences and were spearheaded by Assistant Professor Grant Schauer from the Department of Biochemistry and Molecular Biology at CSU. The study centers around hydroxyurea, a chemotherapy drug often used in clinical settings for cancer treatment, as well as in research where it halts cell development cycles for examination. This halting enables researchers to delve deeper into the complex method of DNA replication that occurs in cells prior to division.
This replication process happens frequently within the body. Nevertheless, complications can arise if the DNA being replicated is altered due to harmful metabolic byproducts, UV radiation, or chemotherapy drugs. When cells experience these issues at critical checkpoints managed biologically, the process is paused to avert any further complications. Hydroxyurea facilitates the investigation of how and when a cell interrupts its replication through activating these checkpoints for exploring the complex biological mechanisms involved.
For many years, it was believed that hydroxyurea worked by stopping the synthesis of DNA building blocks. However, Schauer’s research team observed that the drug was simultaneously generating harmful reactive oxygen species in crucial cell components. Schauer noted that such unintended reactions obscured understanding of the cell’s “kill switch” mechanisms, which are designed to prevent incorrect DNA replication in hostile oxidative conditions.
“Our findings indicate that hydroxyurea interrupts the replication process in a less targeted manner than previously believed,” he explained. “We discovered that oxidation was inhibiting DNA polymerases—enzymes that directly replicate DNA—by attacking iron atoms within these enzymes, rendering them ineffective. This effect lingered even after the drug was removed from the situation.”
To tackle this challenge, the CSU team designed a system that employs genetically modified yeast cells called RNR-deg. This method presents a less toxic and quickly reversible alternative to hydroxyurea for halting the replication process. Given that hydroxyurea is commonly utilized today, this new approach could significantly transform research methodologies regarding cell cycle arrest.
Schauer mentioned that the team utilized flow cytometry to analyze the DNA content and processes within the cells during their research. Funding for this study was provided by the National Institutes of Health, with several undergraduate researchers also playing a role.
Hannah Reitman, an undergraduate biochemistry student, contributed to the paper as an author after gathering and evaluating data for the project. She stated that though the lab work felt daunting initially, it turned into an invaluable learning opportunity.
“Working on this project in the lab has taught me numerous techniques and concepts that I wouldn’t have encountered in a lecture,” she shared. “Working in the lab fosters independence and hones excellent problem-solving abilities. These are skills I will continue to develop throughout my career, and I am deeply thankful for this experience.”
Schauer mentioned that the research team intends to pursue this subject further and aims to adapt the technique for use in human cells.
“The RNR-deg yeast strain emerges as a highly promising and possibly superior alternative,” he noted. “It lacks the adverse effects of hydroxyurea that may have obscured our understanding up to now. This is a significant discovery, and I look forward to advancing our research towards potential applications in human cells in the future.”
