Fundamental insights into gene control
After obtaining a bachelor’s of science degree in zoology from the University of Wisconsin, Groudine received both his MD and PhD from the University of Pennsylvania, where he met fellow graduate student and future close collaborator and friend Harold Weintraub, MD, PhD. During his graduate work, Groudine spent a year as a visiting scientist at the Swiss Institute for Experimental Cancer Research, where he met then-postdoctoral fellow Robert Eisenman, PhD. Groudine, Weintraub and Eisenman would later be colleagues and collaborators at Fred Hutch.
Groudine pursued his dual scientific and clinical training during a residency in radiation oncology at the University of Washington and a concurrent research fellowship in the lab of Fred Hutch physician-scientist Paul Neiman, MD.
Today, we understand that DNA packaging does more than ensure that six feet of DNA can fit into the nucleus of a single human cell. We know that chromatin, the complex of DNA and its packaging proteins, plays a central, controlling role in gene transcription: Tighter DNA bundling helps keeps genes off, while looser bundling makes it easier to turn them on. And we know that how long DNA molecules are arranged in physical space is a factor in gene regulation.
The idea that the state of a gene’s chromatin affected its transcription “was conceptually new at the time,” said Fred Hutch colleague Toshio Tsukiyama, PhD, who studies how cells modulate chromatin to enter and maintain dormant states. “People used to think that chromatin is like a brick: It’s a pretty boring thing you need to have for structure.”
Groudine focused primarily on how cells control expression of the beta-globin genes, which encode hemoglobin, the oxygen-carrying protein present in red blood cells. Globin genes come in three versions: an embryonic, a fetal and an adult version. Red blood cells need to switch globin genes on as they develop — but which version is “on” depends on when in an animal’s life cycle the red blood cell is being produced.
With Weintraub, Groudine used chicken globin genes as a model to show that actively transcribed genes are more “open” (or loosely packaged) than genes that are not transcribed. They developed a molecular tool, using an enzyme called DNase I, to help scientists distinguish between more- and less-condensed areas of chromatin.
“He was fearless in his research,” said Doug Engel, PhD, a cell biologist at the University of Michigan who collaborated with Groudine and Weintraub on their work on chromatin and globin genes. “It’s not a unique characteristic, but it’s detected in the best scientists: They allow their work to do the talking for them. Mark did that.”
Groudine approached chromatin with an open mind and helped reveal its changeable, critical nature. His work on how the relationship between chromatin and DNA structure played into gene expression led him to co-discover locus control regions which are an array of independently acting enhancer elements that activate transcription of genes over very long distances. If the locus control region for a globin gene is missing, red blood cells can’t make enough hemoglobin and a type of anemia called thalassemia develops.
“The work that Mark and Hal did to show that important elements like promoters and enhancers for gene transcription have accessible or open chromatin structure is still true today,” Tsukiyama said. “It’s still the gold standard.”
Enhancers’ ability to affect expression of far-distant genes depends on the way that DNA strands are arranged in 3D space. Groudine and colleagues led work demonstrating that enhancer elements help ensure that genes are accessible to transcription factors (the molecules that transform information in DNA into RNA) by keeping them away from tightly compacted areas of chromatin. He also showed that the location of proteins and genes in different areas of the nucleus plays an important role in developmentally regulated gene expression, and the 3D organization of proteins and DNA within the nucleus changes to help determine which genes are on and off.
“Mark is a very creative thinker who sees the big picture but also does the nitty gritty work to make it real,” said National Cancer Institute Center for Cancer Research Director Tom Misteli, PhD, who also studies the 3D organization of the genome. “He has a high degree of creativity paired with an even higher level of rigor and scholarship. That’s a rare combination.”
Eisenman collaborated with Groudine when their interests in transcription factors and genetic control intersected.
“Mark was always amazing to me. He did great science, he was a very fast and astute thinker and, at same time, he was a practicing radiation oncologist,” Eisenman said.
As practicing physicians, Groudine and then-Basic Sciences Division Director Neiman, who remained a close colleage and mentor throughout Groudine’s career, were rarities in the division. During the early years of his career, Groudine was particularly interested in the use of neutrons in cancer treatment and for many years attended a clinic at UW where patients who had been treated with neutrons were evaluated. Colleagues knew Groudine must be heading to clinic whenever they spotted him wearing a tie.
Groudine also served as a board member at the Seattle Cancer Care Alliance and as a professor of radiation oncology at UW Medical School. In this capacity, he helped bring proton therapy, a more precise form of radiation treatment, to Seattle.
Even when he ventured into new scientific areas, Groudine brought his usual scientific acumen and spirit of collaboration, said Parkhurst. She acted as one of Groudine’s associate directors of the Basic Sciences Division and also worked with him to show that a protein that regulates the cell’s internal scaffolding system also influences gene expression by controlling the 3D organization of DNA in the nucleus.
“He likes to challenge you, and he's got really good ideas. It’s great to have that kind of sparring partner to make your science better,” she said.
Groudine approached his own science in a similar way, said Dirk Schübeler, PhD, who trained with Groudine and now directs the Friedrich Miescher Institute for Biomedical Research in Basel, Switzerland, where he also leads a group dedicated to the study of gene regulation in the context of chromatin.
Rather than defending his models, Groudine continued to challenge and test them, Schübeler said: “That’s the hallmark of rigorous scientist.”
Marjorie Brand, PhD, a cellular biologist at the University of Ottawa who trained with Groudine as a postdoctoral fellow, praised his ability to cut to the heart of scientific problems and identify approaches to solving them.
In recognition of his achievements, Groudine is an elected member of several scientific honor societies, including the National Academy of Sciences, the National Academy of Medicine, the American Academy of Arts and Sciences and the American Association for the Advancement of Science.
Administrative leadership: Weighing the nuances
Groudine also applied his intellect to building Fred Hutch’s culture and community.
“Mark devoted his entire career to shaping the Hutch into a terrific place to do research,” said Barb Trask, PhD, whom Groudine helped recruit to head the Human Biology Division, a position she held from 2000 to 2011.
Groudine fostered an environment that encouraged cooperation and discouraged competition for space or resources, she said: “He set high standards, strove for fairness, recruited great colleagues, and pushed for the infrastructure and resources that Hutch scientists needed to do well.”
By doing so, Groudine strove to carry on the legacy of close friend and collaborator Weintraub, who had helped found the Basic Sciences Division and contributed to its egalitarian, science-first culture. When Weintraub died of a brain tumor at 49, Groudine stepped beyond the lab and clinic.
“Once Hal died, Mark felt very strongly that he wanted to make the atmosphere of the place retain the same values, and he stepped up into leadership,” said longtime Fred Hutch colleague Denise Galloway, PhD, who directs the Pathogen-Associated Malignancies Integrated Research Center and holds the Paul Stephanus Memorial Endowed Chair.
Groudine first helmed the Basic division from 1995 to 2004, then took on center-wide administrative roles as Fred Hutch’s deputy director from 1997 to 2016 and executive vice president from 2005 to 2016. Twice, in 2010 and 2014, Groudine served as the organization’s acting president and director.
“Mark lived and breathed the center, both scientifically and administratively,” said Fred Hutch virologist and President and Director Emeritus Larry Corey, MD. “He was an incredible source of history and knowledge. He knew everybody and was able to liaison between people in a wonderfully unique way.”
Gilliland lauded Groudine’s commitment to maintaining Fred Hutch’s scientific legacy.
“Mark was critical to keeping us a collaborative, well-harmonized institution,” Gilliland said. “He was pivotal in maintaining and developing the egalitarian approach that we have.”
Others noted how Groudine’s talent for seeing the big picture and the details helped him as a steward of the organization.
“He knew how to weigh all of the various indescribable nuances required to make the right decision,” Roth said.
Gilliland, Corey and fellow President and Director Emeritus and Nobel Prize Winner Leland Hartwell, PhD, all praised Groudine’s ability to balance competing needs of a diverse array of faculty members and ensure scientists had the resources they needed. Many Hutch scientists noted how much Groudine’s support helped advance their research programs.
“It was pretty inspiring to watch him take on more and more,” said Senior Vice President and current Basic Sciences Division Director Sue Biggins, PhD. “I noticed he really put everything ahead of himself. Our division and the Hutch benefitted tremendously.”
Parkhurst, whose own commitment to science and scientists was honored with the Groudine Chair, said that it was Groudine himself who showed her that everyone can make a difference.
“Mark was guardian of science at the Hutch,” Gilliland said.