Q&A: Why it’s important for cells to make copies on an exacting schedule

Allison McClure, Ph.D., is an assistant professor in the Department of Biochemistry and Molecular Genetics at the CU School of Medicine. She is focused on learning all about how cells replicate, or make copies of themselves. McClure and her research team seek to understand how cells copy all of their DNA on time and without genetic mistakes to pass down to next-generation cells.

In this interview, she discusses how this works.

How do our cells stay on time and not get delayed when making copies of themselves?

Every cell in our bodies must make copies of themselves to keep us alive. Did you know that the genetic information within each cell that must be copied (your DNA) is the equivalent of a 200,000-page book?

Are cells usually on a tight schedule when replicating their DNA?

“As you might imagine, the process of cell replication is regulated and on a strict schedule, somewhat like writing an article for a newspaper on a tight deadline,” she says.

“You can think of the process of replication like a newspaper journalist interviewing multiple experts about an important new law and then reporting, or replicating, those facts in a news article. The journalist is expected to finish the article for publication in the newspaper by a certain deadline so that the public has accurate information about how the law will apply to them on time before the law goes into effect. Likewise, a cell has a strict deadline to finish replicating all of its DNA before the cell divides.”

McClure’s lab has been working on a surprising discovery—sometimes things stall, and replication of the DNA does not finish on schedule! Her team has seen brand-new copies of DNA being made when the cell has already begun to divide, well after the typical deadline for copying DNA has passed. This delayed timing of replication has brought up a lot of questions that the lab is working hard to answer.

Why might a cell become delayed or stalled when replicating its DNA?

“Thinking back to the journalist, missing the deadline may be due to simple procrastination or not finishing a task on time. But perhaps the delay is due to a problem with the audio equipment? Maybe the interview recording was distorted, and the journalist was stuck without precise quotes from their expert sources. Or, maybe their notes were pushed off the desk and scattered all out of order, requiring more time and help from co-workers to reorganize everything,” she continues.

“No matter which issue came up, the deadline was missed, the reporter required additional help from others, and the article was submitted later than expected.”

Despite the deadline-delaying issues that might pop up, it is also critical that the reporter files a factual story so that inaccurate information does not reach the public.

In a similar way, McClure’s lab is investigating various cell factors that might help a stalled cell restart the replication process after the original replication deadline has passed.

Why is the research that McClure and her team work on in their lab so important?

Cancer cells spread in our bodies when cell replication makes a lot of errors and does not follow the usual schedule. This is why learning how a cell can overcome setbacks in replication is important—one thing this research may help us do is figure out ways to prevent cancer from growing. By working to understand the ways that cells fix stalling during replication, McClure and her team hope to illuminate how cells become cancerous and, ultimately, advance treatments to stop the spread of cancer.