Stony Brook’s Thomsen studies genes in frog development

Stony Brook’s Thomsen studies genes in frog development

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Many expectant parents live their lives somewhere between hope and prayer. The big question, and fear, often isn’t whether the child will be a boy or girl, but whether he or she will develop in a healthy way.

The agony and ecstasy of the process was exponentially more dramatic for Gerald Thomsen and his wife Julia Todorov-Thomsen during three pregnancies that produced healthy children. Scientists who met at Stony Brook, the couple knew each phase of development for the skin, muscles, heart, brain, and everything in between.

“I tried to push out of my mind all the scenarios where things could go wrong,” Thomsen said. “There are so many complicated circuits and events.”

Indeed, Thomsen has considerably more than textbook knowledge about development, albeit with other organisms. The Stony Brook professor in the Department of Biochemistry and Cell Biology has dedicated much of the last 20 years to understanding some of the signals and processes that help animals, in his case, mostly frogs, develop.

The big picture question he explores in his lab is, “How does an embryo put itself together? How do cells with different specialties — nerve cells, skin cells — emerge from a single egg cell?”

Thomsen is interested in exploring this question at the whole animal, cellular and molecular level. In his lab, he is studying a process called induction, in which cells respond to signals from neighboring cells.

When a signal, often in the form of a protein or polypeptide, binds to a cell, it often sends a signal from the cell membrane to the nucleus, where it might start or stop a genetic process.

He’s currently working on how an understudied gene, which seems to regulate cell differentiation, might affect growth. When this gene is taken away, the frog embryo doesn’t develop tissues and organs critical for its survival.

Thomsen said many scientists in the world of developmental biology look specifically at what is new about a cell as it moves from one state to another. They want to know what genes are turning on or off. To explore that, the researchers often block them or make those genes more active, to see how that influences what a cell does.

In the late 1990s, Thomsen and a student of his, Haitao Zhu, observed a protein that interacts with a set of signals that go from the cell membrane to the nucleus, where the frog’s genetic machinery resides. When Thomsen and Zhu put the gene for that protein into the frog embryo, it generated another backbone and nervous system.

“It was really dramatic,” Thomsen recalled. The gene turned out to be a key regulator in a signaling pathway, called TGF beta.

Thomsen’s work in this arena is “a major contribution to our understanding of how embryos develop,” said Amy Sater, a professor at the University of Houston in the Biology and Biochemistry Department. “It’s had applicability across all vertebrate systems.”

Sater and Thomsen have taught the Cell and Developmental Biology of Xenopus course at Cold Spring Harbor Laboratory for the last three years. Sater has appreciated Thomsen’s sense of humor and said, “The community has a lot of confidence in [his] work.”

Thomsen has a grant right now from the Stony Brook Medical School to look at a protein to see whether it might be operating in breast or other cancers. His lab, which includes eight people, is also focused on understanding the signals that lead to regeneration. In this arena, he is studying frog and sea anemone embryos.

Adult anemones can regenerate a complex body part from a stump of tissue, he said, the same way starfish can. Frogs have a limited ability to regenerate, so he could potentially test the lab’s findings with sea anemones in frogs.

A resident of Port Jefferson, Thomsen brings special guests to his children’s classes, introducing them to adult frogs, embryos and tadpoles. His children are Liam, 7, Isabella, 5, and Luca, who is almost 3.

Initially interested in oceanography, a specialty his wife pursued, Thomsen was fascinated by biochemistry and gene regulation in the context of differentiating cells. His particular field “always has something new.”

As he felt when his children were developing, Thomsen said the process is “amazing. Even though we know a lot of detail, we also appreciate that we know these details in a spotty way.”