Not Your Average Lab Rat

By Jade Boyd

When you look in the mirror, you wouldn’t expect to see a zebra fish staring back, but you have more in common with them than you may realize.

Zebra fish cost about a dollar each at the pet store, adults can lay up to 500 eggs at once and the fish grow from eggs to hunting their own food in just three days. “Even so, humans and zebra fish aren’t that dissimilar,” said assistant professor of biochemistry and cell biology Mary Ellen Lane, who is Rice’s resident zebra fish expert. “For every zebra fish gene we isolate, there is a related gene in humans.”

Zebra fish — like rats and fruit flies before them — are becoming regular contributors on research ranging from cancer to cocaine addiction. For example, zebra fish were used in a landmark 2005 study that led scientists to the human gene that regulates skin color. It helps that zebra fish embryos grow from just a single cell to having a forebrain, hindbrain, spinal column and eyes in a scant 24 hours. It also helps that the embryos are transparent and develop outside their mothers’ bodies — and thus can be observed under a microscope during every step of their development.

“It’s a beautiful organism for experiment,” Lane said. “It develops in a very regular way, so any abnormality is easy to spot, even for undergraduates with only a few days of training.”

“It’s a beautiful organism for experiment. It develops in a very regular way, so any abnormality is easy to spot, even for undergraduates with only a few days of training.”

- Mary Ellen Lang

Lane’s zebra fish studies explore one of the major unexplained areas in developmental biology: how the brain and central nervous system develop. In her latest work, Lane, assisted by graduate students Catherine McCollum and Shivas Amin and undergraduate Phillip Pauerstein, zeroed in on a gene called LMO4 that’s known to play roles in both cell reproduction and breast cancer. Using the tools of biotechnology, the team studied zebra fish that couldn’t transcribe the LMO4 gene and observed marked enlargement in both the forebrain and optical portions of the embryos. When the fish overexpressed the LMO4 gene, making more protein than normal, those same areas shrank. The findings appeared in the journal Developmental Biology.

“The study suggests that LMO4 independently regulates two other genes that promote growth in those areas of the embryo,” said Lane. “It fills in another piece of the bigger picture of what’s going on during neurological development.”

Lane established Rice’s zebra fish program six years ago. She said the program got a major boost in 2003, when fellow zebra fish researcher Dan Wagner joined the faculty. Their facility houses 18,000 zebra fish and employs a full-time fish caretaker. They recently won funding from Rice’s Faculty Initiatives Fund to hire a research scientist to oversee collaborative research with partners in the Texas Medical Center.