Updated March 10, 2015 at 3:38 p.m.
“Gene expression is really simple. Everyone should know it and feel comfortable thinking about it,” said Nobel laureate Craig Mello ’82, professor of molecular medicine at the University of Massachusetts Medical School, at a lecture Saturday morning in a packed Salomon 101.
Mello’s keynote lecture, entitled “RNA memories: Secrets of inheritance and immortality,” kicked off Day of Biology, a day-long event commemorating life sciences at Brown.
The Day of Biology was dedicated to Marjorie Thompson ’74 PhD’79 P’02 P’07 P’09 P’12 P’14 P’16, associate dean of biological sciences, who died in September. In her more than 30 years at the University, Thompson left an indelible mark, fostering relationships with students, faculty and community members.
Mello’s lecture was followed by colloquia on a variety of topics in biology as well as current relevant University research. The day concluded with a tribute to Thompson, during which administrators announced the creation of an endowed award in her memory.
Mello provided an introduction to genetics before delving into his own research on RNA interference, which won him the 2006 Nobel Prize in Physiology or Medicine.
He began by discussing germ lines, the cells used for sexual reproduction. “Germ lines exist on a cosmic time scale. Every animal on this planet is related to each other — we’re all related to each other.”
The germ lines of humans and nematodes — also known as roundworms — “have journeyed together on this planet for 3 billion years,” he said, adding that a wide range of animal biology can inform the study of human anatomy and physiology.
Mello discussed the relationship between DNA, RNA, ribosomes — the part of the cell that creates proteins — and gene expression. DNA encodes information that is transformed into messenger RNA, which brings the genetic information to the ribosomes, linking amino acids in ordered pairs to create an organism’s proteins.
Mello said there are four building block nucleotides that combine to form codons, which code for the twenty amino acids — the precursor molecules of proteins.
“Four letters in the alphabet make 20 different words, which are the amino acids,” Mello said, adding that “RNA is really simple, but proteins are really diverse.”
Mello also discussed his research on RNA interference, for which he and his collaborator Andrew Fire, professor of pathology and genetics at the Stanford University School of Medicine, shared their Nobel Prize. RNA interference can turn genes off, preventing their expression in the organism and its offspring.
“We discovered that cells need a search engine,” Mello said. “They’re dealing with information in much the same way that we all do on the (Internet). The precise chemical information allows a query to precisely identify a matching RNA cell.”
By targeting messenger RNA, Mello and Fire “learned how to enter search queries inside of cells. We can find genes and regulate them. This is really transforming what we can do in the laboratory.”
Using the mechanisms of RNA interference, researchers can now selectively turn genes off, he said.
This method also has implications for repairing stem cells, Mello said, adding that, “We can modify the human germ line, but it’s not safe yet.” Researchers can also genetically modify organisms to model human disease for research.
“We’re at a time where we really need to educate the public about what we’re doing. As scientists we don’t often educate people about what’s happening, and I think that creates fear,” he said.
The lecture was followed by a question-and-answer session, during which medical professionals and undergraduates posed questions about gene therapy and pursuing careers in research.
“If you want to be a good scientist, follow your passion,” Mello advised.
A previous version of this article misquoted Mello as saying that the germ lines of humans and nematodes “have journeyed together on this planet for 3 million years.” In fact, they have done so for 3 billion years. The Herald regrets the error.
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