Nobel Laureate Oliver Smithies’ 60 years of research as a bench scientist are meticulously recorded in nearly 140 notebooks spanning his entire career, from his time as an undergraduate student at Oxford, through the groundbreaking research that led to the Nobel Prize, and up to the present day. The notebooks chronicle six decades of scientific research by Smithies, who was awarded the 2007 Nobel Prize in Physiology or Medicine for his discovery, along with Mario Capecchi and Martin Evans, of a process for introducing specific gene modifications in mice using embryonic stem cells.
Last July, Oliver Smithies, D.Phil., Excellence Professor of Pathology and Laboratory Medicine at the University of North Carolina at Chapel Hill School of Medicine, delivered the 2009 Earl H. Morris Endowed Lecture in White Hall. With wry humor, a childlike curiosity, and an obvious love for science, the 84-year-old Smithies held the overflowing audience enthralled as he used pages from his notebooks to illustrate the life of a scientist.
Mother’s starch leads to improved gel electrophoresis
According to his notebooks, the work that eventually led to the Nobel began January 1, 1954. Working at a laboratory in Toronto, he was doing electrophoresis of insulin on filter paper. “I was trying to get the insulin to behave properly and was rather frustrated,” he said. He found another method using starch, but it was very labor-intensive. Then he remembered his mother cooking up starch for his father’s collars when he was a child. “And I thought, well if I cook the starch up and make a gel… I can stain the gel, and I will see the bands very easily,” he said.
“I found out that, sure enough, insulin migrated as a band, and that was very satisfactory.
“By chance I had invented an important method,” said Smithies. His discovery greatly improved gel electrophoresis, a process of separating proteins to identify genes using starch, and became standard in laboratories. Curious, he decided to try a plasma protein in the gel. At that time, only five plasma proteins were known. The next day he found a total of 11 components.
Just before publishing, he ran a sample of another individual in his study. “It was very strange,” he said. “You can see all these bands are there, which were not in the previous sample.”
It turned out to be an inherited difference in the haptoglobin protein, which binds hemoglobin. He collaborated on the research with Norma Ford Walker, Ph.D., professor of human genetics at the University of Toronto and director of the newly formed Department of Genetics at the Sick Kids Research Institute.
He remembered visiting Walker’s clinic. “It was a rather sad, because people would come with problems you couldn’t do anything about,” he said. “I remember a little child, a beautiful little girl with cystic fibrosis. At that time there was nothing that could be done.”
Together Smithies and Walker discovered there was one gene difference in the haptoglobin protein sample. He decided to find what that difference was.
Gene recombination possible
He began to work with DNA instead of proteins. He was trying to determine which genes are related to hemoglobin synthesis. His work with fetal and adult globin genes found two genes that exchanged sequences at the DNA level by homologous recombination. “I began to think maybe we can use this homologous recombination to do something useful,” he said.
Then, while teaching, he read a paper by another researcher that demonstrated a process to isolate rare pieces of DNA. Smithies decided to try this process to find out if homologous recombination or gene targeting was possible. “It went pretty quick,” he said. “That paper was April 2, and here’s my note on April 22 on how to have an assay for gene placement. This page, of all of my notebooks, is probably the best page of any page. Because on it are all the principles that show that gene targeting is possible.”
Your experiment is just not going to work
He decided to make things simpler, but then a student pointed out a flaw in his experiment. “She said ‘You know, Oliver, your experiment is not going to work. You’re looking for a way of introducing DNA into the beta globin locus, and you’re using bladder carcinoma cells. Bladder cells don’t make hemoglobin. Even if you put a selectable gene in there, it probably won’t be expressed.’
“So what did I do? I went flying,” Smithies said. An avid pilot, he flew off with friends and went sailing in the Florida Keys. “I came back all full of life. I’m going to start again, and I’ll now use cells that are making hemoglobin, and then I won’t have a problem.”
But to use the new cells, he needed a special apparatus to punch holes in their membranes. So he made one out of a baby bathtub, an old test tube rack, and bits and pieces from Radio Shack. “That was the apparatus,” he said, “which did the critical experiments for showing that gene targeting was possible.”
According to a page from his notebook three years after the April 22 entry, this was the first demonstration that it was possible to modify a gene in a planned way.
It might be possible to make a mouse
But how could it be used? “It wasn’t any good for gene therapy. It was much too rare for use in gene therapy,” he said, “but it might be possible to make a mouse.”
Smithies knew of Martin Evans’ work on embryonic stem cells in mice, so he asked Evans for some of his cells. “This is another good lesson for students: never hesitate to ask another scientist for help,” he said. “Most often you will get help.”
Smithies’ experiment with Evans’ cells worked the first time. “Some experiments do,” he said. “So we knew it was possible to make mouse embryonic stem cells, and we could then make an animal from it.”
Showing a photo of the first animal model they made, he said, “It’s a little bit special for me, because, see, it’s cystic fibrosis. You remember me telling you about the little girl, and that we couldn’t do anything. It was very emotional to say that we can make a model of that disease in a mouse that might help other people with cystic fibrosis in the future.” His lab had produced the world’s first animal model of cystic fibrosis.
It helps if you’re born with happy genes
Smithies offered advice to researchers when their experiments don’t work. “Most experiments don’t work, really,” he said. “That’s why I say it’s very important that you find something that you enjoy doing. You have to learn to enjoy every day and not depend on it necessarily giving you the answer that you want. It helps if you’re born with happy genes. It turns out I am.”
Today, Smithies is still working on weekends. Why? “Because it’s fun,” he said. “The best days of the weekend are the days when I do an experiment. I go flying, I take (my wife) Nobuyo to lunch, then I do an experiment.”
He said he doesn’t know what the future may bring, “but that’s what makes science exciting. Because you don’t know what’s on the next page.” VS