Late one evening in November of 1985, Fenyong Liu and a group of friends arrived in Shanghai after a 10-hour train trip from Hefei in China's Anhui Province, where they all attended the University of Science and Technology of China. They had come to take the Graduate Record Examination (GRE).
"There were only two testing centers in China, in Beijing and Shanghai," Liu says. "You have to pay the testing fee in U.S. dollars. ... One test probably took 6 months' salary." Paying for the test was enough of a challenge; a hotel was out of the question. So, after their train arrived at 10 p.m., he and his friends spent the night wandering Shanghai's streets, waiting for the testing center to open.
Liu, now 46, overcame a poor night's sleep -- and numerous other financial, cultural, and language barriers -- to take his GRE, move to the United States to study virology and microbiology, and eventually land his current post as a professor of infectious diseases  at the University of California (UC), Berkeley, School of Public Health . At Berkeley, Liu studies the biology of cytomegalovirus (CMV), a member of the herpes virus family that can cause serious birth defects, including liver damage.
That future was far from set in 1986, when his family used up their savings to send Liu to the United States. "My parents bought a one-way ticket from Hong Kong to Chicago and told me, 'If you don't finish your studies, don't come back.' "
Liu started grade school during Mao Zedong's reign. "My early schooling ... was at the height of the Cultural Revolution," he says. "You learn Chinese. You learn communist theory, a little literature, but other than that, not much going on."
Liu's mother, a high school teacher, made sure Liu and his brother had books to supplement the rudimentary education offered by the era's schools. Liu's father, who came from a working-class family and attended only grade school, insisted on doing the cooking and cleaning so the boys would have time to study.
Mao died in 1976, when Liu was 12 years old. Deng Xiaoping came to power and began to restore China's educational system. Seeing an opportunity, Liu's mother petitioned to have her son transferred to the junior high school where she taught, a more academically rigorous school than the one he had been attending.
Even at the more challenging school, Liu was able to finish his work with time to spare, so his mother provided science books to supplement his classes. When he finished junior high at age 15, Liu decided he was ready for college. His mother disagreed, and university policies made it impossible for so young a student to enroll.
So Liu had no option but to attend high school. After taking state exams, he was admitted to the top high school in his region, a boarding school. "My mother was not happy," he recalls, but she let him go.
His high school physics teacher recognized Liu's scientific talent and recommended him to the University of Science and Technology  of China, one of the country's top universities. Liu enrolled there at age 17, in the department of modern physics. Once again, Liu sped through his classes, and once again his plans for an early exit were foiled: Although he completed the coursework for the physics major in just 2 years, the school did not permit early graduation.
"At that time, China was not flexible," Liu says. "They say, 'If you graduate early, who will take your spot?' " He decided to start over with a new major -- biology. People told him to say he chose the new major because he was interested in biology, he says. "But that's not true. I just wanted to learn."
It was a fortuitous move. Liu met his future wife in the biology program, and he met a biology professor who knew a researcher from Chicago Medical School , Kwang-Poo Chang , who was interested in helping Chinese students attend graduate school in the United States.
Liu wrote to Chang, who wrote back and explained that Liu would need to take the GRE and the Test of English as a Foreign Language before applying to the university. So Liu made two journeys to Shanghai for the tests. Liu's scores were not up to the standard of his usual stellar performance on Chinese national exams. He did well on the analytic and quantitative sections -- but terribly on the language tests.
Yet the Chicago Medical School decided to give him a chance -- and a fellowship. When his classes started in the fall of 1986, he struggled with English. At first, he couldn't understand his professors at all. When he had the chance to meet the chair of his department, the two had to communicate through written notes. Fortunately, a university co-op service provided notes from the lectures, which he studied along with his books; in fact, he says, he did little besides study. He didn't think he had the free time to take language classes, but his English improved -- slowly. Some of the faculty members were surprised when he aced his midterms. Chang wasn't.
"He [had] graduated from one of the top two universities in China. He learned very quickly," Chang says. After one semester at the Chicago Medical School, Liu applied to the University of Chicago , with Chang's support, and he was accepted. "It was a loss for me and my department, but for his career it was a good thing," Chang says.
Liu landed in the lab of Bernard Roizman , one of the leading experts on herpes simplex virus 1. Liu's first project, on viral DNA replication, failed after 2 years, so he switched gears. Protease inhibitors were showing promise as AIDS drugs; Roizman asked Liu to look for a protease in the herpes 1 virus. When Liu succeeded, Roizman told him to write up the results for publication. After weeks of effort, Liu says, he was still struggling, so Roizman spent 2 days going through the draft line by line, improving the manuscript and helping develop Liu's writing skills. The result was a publication and a patent, licensed by the university to Bristol-Myers Squibb. "He split the royalties evenly," Liu recalls. "He didn't have to. He never asked. He just did it."
Roizman also counseled Liu, who was fielding job offers from pharmaceutical companies, to give an academic career a try. By then, Liu had married his wife, who finished her studies at the university in China and went on to graduate school at Yale University. While Liu was working in Roizman's lab, they managed to see each other just a few times each year.
Roizman told Liu to "go to Yale and be with your wife and find a postdoc" -- so Liu joined the lab of Sidney Altman , who won the 1989 Nobel Prize in chemistry  for work on the catalytic properties of RNA. Liu wanted to learn molecular biology, and Altman's lab was a place to do it; his research there on using Ribonuclease P to cleave messenger RNA led to three more patents, which Yale licensed to a biotech start-up.
As he was finishing in Altman's lab, UC Berkeley was looking for a virologist, and Liu interviewed for the position. When Berkeley made him an offer, Liu turned to Roizman for help choosing a research problem. "He told me, 'When you start your career, try to study something new, very, very different than when you are a student,' " Liu says. Roizman pointed out that CMV, was a relatively unstudied herpes virus. Liu had launched his career studying herpes simplex virus 1, a close enough cousin to CMV that he figured he could get funding to study it.
Altman offered to let Liu stay at Yale and work on his first grant proposals while he prepared for the move to Berkeley. He and his wife -- who now runs her own lab at Berkeley studying Salmonella -- had just had the first of their two children.
"Writing grants, writing proposals, it was very hard," Liu recalls. Altman offered one of his own grants as an example and gave Liu feedback on his own efforts. "I asked him to critique my grant. I think it was very generous [of him] to spend so much time."
Liu is still in touch with both Roizman and Altman and grateful for their mentorship.
"I'm really grateful to the people who have mentored me. They not only taught me how to do good science, they taught me how to be a good person," he says.
Today, as a tenured full professor at Berkeley, he fills that role for his own students. He's brought two Chinese students to his lab for their Ph.D.s and mentored exchange students from Chinese universities who've come to his lab to complete their thesis research. He helps bring visiting scholars to the school and runs an active research lab that trains students from a range of backgrounds. His five current R01 grants support research on drug targets in CMV as well as potential therapeutic agents. He tries to give his protégés the same kind of support he received. So far, he has filed two more patents, this time with his students.
"He has a great future," says Z. Hong Zhou , a professor of microbiology, immunology, and molecular genetics at UC Los Angeles -- and Liu's classmate at the University of Science and Technology of China. "I'm always saying I'll see him in Stockholm someday."
Photo (top): Cytomegalovirus placentitis, credit: Ed Uthman 
Robin Mejia  is a science writer in Santa Cruz, California.