Lin He: Mesmerized by micro

© Eric Millette

Assistant Professor of Cell and Developmental Biology at University of California, Berkeley. Age: 36

Lin He didn’t learn much biology in high school, as secondary education in her native China focuses more on math, physics, and chemistry. That “limited exposure” made biology “very mysterious,” recalls He, who decided to make it her major when she got to college. After just 2 years working in a lab, trying everything from dissections to molecular experiments such as site-directed mutagenesis in firefly luciferase, she was certain that biology would be her career.

The next step was a graduate education. Inspired by her professors and other researchers who studied and worked in the United States, He decided to head to America for her PhD. She joined the lab of geneticist Greg Barsh at Stanford University, to whom she credits her maturation into a confident scientist. But...

METHODS: After writing a review article on the young field of microRNA research with Hannon,1 He had the idea to characterize the function of microRNAs by screening for their expression patterns in cells. Using a microRNA microarray, developed in collaboration with Scott Hammond at the University of North Carolina, He compared the expression of microRNAs—known as the mir-17–92 polycistron—suspected of playing a role in tumorigenesis in cancerous and normal cell lines. She found that microRNA levels were substantially higher in the cancer cells, which glowed green, indicating the presence of He’s GFP-labeled microRNA molecules.2 “The results came out as beautiful as you can possibly imagine,” she recalls. “That was probably one of the happiest moments in my postdoc [career].”

RESULTS: He spent the rest of her postdoc unearthing novel functions of microRNAs. Turning her focus to the widely studied cell cycle regulator p53, she identified a family of microRNAs known as miR-34s that appear to play a critical role in the p53 tumor suppressor pathway—overexpression of mir-34s in mouse embryonic fibroblasts inhibited cell growth and caused cell cycle arrest.3

DISCUSSION: In 2008, He joined the faculty of the University of California, Berkeley, where she searches for more new microRNAs and other noncoding molecules involved in tumorigenesis and tumor maintenance, examining their potential as diagnostic tools and targets for cancer therapy. “She has demonstrated in all aspects of her life the ability to recognize and pursue opportunities in a way that makes use of advances in technology,” Barsh adds, “[getting at] the most interesting and practical questions that are available at the time.”

He’s current projects continue to characterize the role of microRNAs in cancer, specifically aiming to nail down the molecular basis of mir-17–92’s oncogenic effects and how exactly mir-34s participate in the p53 tumor suppressor pathway to prevent malignant transformation. “microRNAs and cancer was a hot field, [and] it still is,” says Hannon. “Lin is certainly among the best of that crop.”

Literature Cited
1. L. He and G.J. Hannon, “MicroRNAs: small RNAs with a big role in gene regulation,” Nature Review Genetics 5:522–31, 2004. (Cited in 514 papers)
2. L. He et al., “A microRNA polycistron as a potential human oncogene,” Nature, 435:828–33, 2005. (Cited in 764 papers)
3. L. He et al., “A microRNA component of the p53 tumour suppressor network,” Nature, 447:1130–34, 2007. (Cited in 257 papers)

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