For long-time friends, neighbors and University of Wisconsin Oshkosh chemistry department colleagues James Paulson and Linfeng Xie, 2018 has been an extraordinary year.
While publishing in a prestigious journal like Cell, Nature or Science once in an academic career is considered a distinctive accomplishment, twice in the same year is extremely rare and difficult.
But that’s exactly what this research duo has done.
First, they were part of a team of scientists from around the world that in January published in Science an article entitled “A pathway for mitotic chromosome formation,” which shed light on the structure of chromosomes.
Then just late last month, Paulson and Xie were part of another team that also published in Science. This time, “An intrinsic S/G2 checkpoint enforced by ATR,” described their work that uncovered the existence of a new, previously unknown, checkpoint in the cell division cycle.
“I’d say 2018 has been going very well for us, Jim,” said Xie, as he nodded to his colleague with a smile.
Colleen McDermott, acting dean of UW Oshkosh’s College of Letters and Science, agreed.
“Drs. Paulson and Xie have contributed greatly to the field of biochemistry with outstanding research on cell cycle regulation,” she said. “Not only are these two professors from the chemistry department noted researchers, but they also are excellent teachers and include our students in much of their research. They exemplify what the College of Letters and Science is about.”
A fourth check point in cell division
In the Aug. 24 Science article, the researchers—led by Joshua Saldivar of Stanford University School of Medicine—described the existence of a new checkpoint that prevents cells from progressing toward mitosis until DNA replication is completed.
“When cells grow and multiply, they go through a serious of stages or ‘phases’ called cell division,” Paulson said. “There are four main phases of cell division. After the cell has divided, the ‘daughter’ cell first has a period of time where it builds up its resources and gets ready to duplicate its DNA. In the second phase, the DNA is replicated. In the third, the cells gets ready to divide, and in the fourth, it undergoes cell division (mitosis) to produce two cells, where there was only one before.”
Throughout this cell division cycle, there are “checkpoints,” where mechanisms prevent the cell from going to the next phase until it is ready, he explained
Previously, three major checkpoints were known.
“This new, fourth checkpoint prevents the cell from progressing toward mitosis until DNA replication is completed,” Paulson said. “If the cell started to divide before all the DNA was copied, it would be a disaster.”
For their part in the research, Paulson, a biochemist; and Xie, an organic chemist, synthesized and provided the compound that was necessary to do a control to confirm the scientists’ interpretation of their findings.
The two said publishing the pair of articles in Science in 2018 has been especially significant considering the long-time close friendship between their families.
The strong working relationships between faculty members in the entire UWO chemistry department also have contributed to Paulson and Xie’s success.
That collegiality was even a factor in Xie’s decision to accept a position at UWO in 1993.
“We’re all working on completely different things, but we all support each other,” Xie said. “We have good resources, and we all just want to pursue knowledge and know more.”