Photo by Ignacio Lobos
Image by Dr. Andrew Taylor
When Dr. Andrew Taylor sits down at an electron microscope, he is more than a dedicated scientist. "What Andrew does at the electron microscope is truly an art as much as a science," said Dr. Gerry Smith, a principal investigator in the Basic Sciences Division.
Smith ought to know. He's been Taylor's supervisor for nearly 30 years — the last 25 at the Hutchinson Center, where Taylor's work as a staff scientist in Smith's lab has unlocked important secrets about how broken DNA molecules are repaired.
"He's one of the few people in the world who gets beautiful pictures of DNA molecules using the electron microscope," Smith said. "He didn't invent the technique, but after 30 years he's become very skilled at capturing highly revealing images."
Taylor accepts the compliment, but gives the Center credit for making electron microscopy available as a shared resource — saving individual labs the huge cost and trouble of buying and maintaining their own electron microscopes.
Beyond-the-lab scientific contributions
"Electron microscopes are expensive and sophisticated pieces of equipment that need someone to look after them," Taylor said. "The Center's shared-resource model is a good way to go and incredible for me. Otherwise, either we wouldn't have the equipment, or we'd spend all of our time fussing with it."
Sharing the credit typifies Taylor's generous personality. "If someone comes to him with a question, he'll stop whatever he's doing and help them," Smith said. "Whenever new people come to the lab or someone needs to learn a new technique, I send them to Andrew."
Taylor's contributions extend beyond the lab. In 1989, he became the first Hutchinson Center employee to donate bone marrow through the National Bone Marrow Donor Program. The program enables patients without matching relatives to receive donations from unrelated matching donors.
Taylor joined Smith's lab in 1978 when Smith was a faculty member in the Institute of Molecular Biology at the University of Oregon. When Smith moved to the Hutchinson Center four years later, he brought Taylor with him.
"Andrew is an excellent scientist," Smith said. "He does great experiments and he's totally reliable. When he does an experiment, I know that it's done right."
Taylor also is a "character" whose dry — some might say obscure — sense of humor can stump even those who know him well. "Sometimes I get it and sometimes I have only the faintest idea," Smith said.
Originally from England, Taylor came to the United States in 1976 to pursue postdoctoral studies at Johns Hopkins University. Before that, he earned a bachelor's degree in molecular biology at the University of Edinburgh and a doctorate in virology from the University of Glasgow.
"Molecular biology was an up-and-coming field," Taylor said of his choice of studies. "Almost every major advance has happened during my lifetime starting with Watson and Crick."
Taylor's work may not be on par with the duo who deciphered the structure of the DNA molecule in 1953, but his ongoing investigation of the RecBCD enzyme in a model organism — the widely studied E.coli bacterium — has made him a leading authority on that complex and sophisticated enzyme. "He's studied it longer than anybody else in the world," Smith said.
Why does one enzyme merit a lifetime of study? Because of the many functions it performs in the repair of broken DNA molecules. Taylor calls it the "Swiss Army knife of recombination" with a new "blade" being discovered every five or six years.
DNA molecules routinely break. Recombination enables them to be repaired without losing any bits of the genetic blueprint they carry. If bits are lost, it can lead to death or diseases such as cancer. "Figuring out how recombination works is my life's work, and Andrew has been involved at every step," Smith said.
The RecBCD enzyme was known to be involved in recombination when Taylor began studying it in 1978. However, he was the first to discover that the enzyme creates a loop of single-stranded DNA as it unwinds double-stranded DNA molecules during recombination. A footnote: Back then, the enzyme was referred to as RecBC because the D subunit had yet to be found — by Taylor and his colleagues in the Smith Lab.
In 2003, Taylor identified yet another remarkable RecBCD characteristic. Enzymes such as RecBCD that unwind DNA are called helicases. A single "motor" powers most helicases as they travel along DNA strands unwinding them in preparation for recombination, repair or replication. Taylor found RecBCD has two motors — a fast one and a slow one that creates the loops he had discovered earlier.
The mechanics of RecBCD's unique behavior isn't fully understood, but the more scientists learn about recombination in simple model organisms such as E.coli bacteria, the better they can pursue the secrets of human recombination and DNA break repair.
The work continues. Taylor and Dr. Sue Amundsen, also in the Smith Lab, recently found yet another function performed by Taylor's biological Swiss Army knife. During recombination, RecBCD snips DNA at specific "hot spots" based on signals it receives from a specific nucleotide sequence within the DNA.
Taylor was instrumental in determining the molecular nature of these hot spots — their nucleotide sequence and their interaction with RecBCD enzyme. The latest discovery by Taylor and Amundsen indicates that RecBCD experiences a cascade of signals, transmitted from subunit to subunit, after the hot-spot encounter and regulating the enzyme to properly repair broken DNA.
"I've been working on this enzyme for 30 years, but in the beginning none of us imagined how complex it would be and how many things it would do," Taylor said.
Taylor's wife, Dr. Meg Holmes, also works at the Center as an X-ray crystallographer in Dr. Roland Strong's lab. For a brief time, their son, Nick, and daughter, Ely, worked at the Center part time while in school. As circumstances would have it, the entire family worked on the same day just once, but they made the most of it. "We all went out to lunch," Taylor said.
After 25 years at the Center, the thing Taylor appreciates most is the camaraderie.
"This is a wonderful place to work because it's an institution full of enthusiastic people who are not only enthusiastic about their own work, they're also happy to stop and give you a hand with your work," he said. "All you have to do is walk down the hall, and sooner or later you'll bump into somebody who can answer your question."