Chris Lassiter, Roanoke College – Estrogen

On Roanoke College Week: How do our organs end up in the right places?

Chris Lassiter, associate professor of biology, explores the role estrogen plays in putting us together.

Dr. Chris Lassiter is an associate professor of biology and Roanoke College’s director of undergraduate research. His research interests lie in the field of developmental biology; his work has focused on the estrogen and androgen signaling pathways and has involved characterizing the estrogen receptors, androgen receptors, and aromatase, the gene that codes for estrogen synthesis from testosterone. He and his students study these receptors and codes in zebrafish.



Have you ever wondered how we develop from a single cell into a complex organism with all of our organs in the right place?  As embryos, that single cell divides repeatedly to create all the cells in our body, communicating with one another to get organs in the right place.  Genes turn on and turn off, creating the pancreas over here, the eye over there, and growing out a limb bud to form an arm or leg. 

One of the signals that cells use to communicate is estrogen.  Estrogen is not just a female hormone, but is used by both males and females in both embryos and adults.  Estrogen itself, however, won’t communicate successfully in the body unless the body has a way to detect estrogen.  In our bodies, we use an estrogen receptor to receive and interpret the estrogen signal.

To study estrogen signals, we can use animals that resemble humans in their embryonic development.  One popular model is the zebrafish, who share around 70% of their genes with humans.  Because of this, scientists can study how organs develop in zebrafish and apply that to humans.

In our research, we use zebrafish to study estrogen during development – and what can happen when excess estrogen from the environment is present.  We have found that estrogen signals have significant effects on the developing heart and jaw.   Additionally, estrogenic chemicals in the environment, known as endocrine disruptors, bind to estrogen receptors in our bodies and interfere with normal development – one example is atrazine, a compound used as an herbicide.

Examining zebrafish helps us understand the role of estrogen in building an embryo, and gain a better understanding of human conditions such as heart disease and cleft palette.  And our knowledge of how endocrine disruptors impact the embryo assists us in understanding the environmental impacts of pollution.

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