For Yixian Zheng, boredom has spurred scientific discovery.
Through graduate school, four years as a postdoctoral student at UCSF, and several more years after that, Zheng studied microtubules, which buttress the cell's structure. They also serve as cellular sheepdogs, guiding proteins, organelles, and chromosomes to their needed places around a cell. As a postdoc, Zheng purified the gamma-tubulin ring complex, a group of proteins that helps microtubules form.
Then Zheng changed direction a bit and discovered that an enzyme named Ran helps build the mitotic spindle, the umbrella-like structure made of microtubules that pulls chromosomes apart during cell division. After a cell divides, Ran also helps recreate the nuclear envelopes around the daughter cell nuclei.
Over the years, Zheng became one of the world's leading experts on the mechanisms of eukaryotic cell division. But there's still a lot to know, she says. "A cell is as complex as the universe."
About six years ago, Zheng's inspiration stalled and she considered leaving science. But after reading widely, she saw an opportunity to use Ran to study the evolution of eukaryotes. Ultimately, her lab began looking at mitosis, cell structure, and cell differentiation from an evolutionary perspective. This led to a focus on the mitotic spindle matrix, or what Zheng calls the "fabric on the tent poles."
The spindle matrix helps coordinate the "organized scrambling" of mitosis and then return the cell to interphase, so it can function in tissue.
Zheng's lab is defining the components of the spindle matrix and how and when it's assembled, as well as how it communicates with microtubules. They're also examining how this communication plays out during the differentiation of an embryonic stem cell. "We are finding some very early cellular morphological changes during differentiation that we don't think can be solely explained by transcriptional changes," Zheng says.
"Most people don't really care about what happens to the structural components of a cell. They are looking at signal transduction or transcription, but that's not enough," she says. "The cell is a structural system, and you have to understand how the components of the structure talk to one another to understand behavior."
Zheng grew up in China's Sichuan Province wanting to be a writer. Her parents, both engineering professors, wanted Zheng to follow in their footsteps after college. She was holding out for a writing career. After a 12-hour argument, they settled on a compromise: biology. Even so, she says, "I tried to change my [undergraduate] major from biology to literature after the first year, but at that time there was no way to switch your major. The system in Chinese universities was very strict."
She taught at Southwestern Agricultural University in her hometown Chongqing for two and a half years after graduating, thinking she'd have time to write. Instead, she was bored and found she had little to write about. Her father, then on sabbatical at Akron University in Ohio, urged her to come to the United States. When she agreed, she never imagined that she would stay in the United States, or in science. Zheng entered graduate school at Ohio State and started working in Berl Oakley's lab on microtubules. "Berl showed me how much you could use your imagination and writing skills in research," she says.
Zheng lives in Baltimore with her husband, Max Guo, and their teenage son, Benjamin. Her outlook on her son's potential career plans—he composes piano pieces but plans to study neuroscience—also sounds like a personal philosophy: "You have to make a living, but you are the luckiest person if you can do that and enjoy it."
