FISH CELLS SHED LIGHT ON FACES.

Byline: Greg Bolt The Register-Guard

It doesn't yet explain Mona Lisa's enigmatic smile, but new research at the University of Oregon is shedding light on how faces come to look like they do.

Gage Crump, a postdoctoral researcher at the UO, is using a small species of tropical fish with glow-in-the-dark cells to learn how facial structures form.

In research recently published in a scientific journal, he identified a gene that guides the formation of zebrafish jawbones and showed how problems with that gene lead to deformations in the fish heads.

The zebrafish genes correspond with genes in humans that are involved in the developing facial structure. Although still in its early stages, the research eventually could help lead to better screening for craniofacial diseases as well as a better understanding of the basic processes that shape each individual's facial appearance.

Crump, who works in UO professor Charles Kimmel's developmental biology lab, said the research stems from his interest in the cellular groundwork that causes living organisms, including people, to look like they do.

"In general I'm interested in how animals acquire their particular shape," he said. "How do cells know to form a particular shape that's highly functional?"

Like many cell biologists, Crump uses the 2-inch-long zebrafish as a model for human development.

The UO is a world leader in the use of zebrafish for genetic and cell research and maintains a large laboratory that supplies zebrafish for research on campus and at universities around the globe.

Crump used zebrafish that have been genetically altered to carry a fluorescent protein taken from jellyfish that's designed to cause specific tissues to glow green.

Using a standard research technique, he induced random mutations in the fish and looked for one that had defects in the bones that form its head.

He looked at thousands of mutations over the course of a year before he found what he was looking for: a mutation in the cartilage that later forms fish jawbones.

Zebrafish and humans share a large number of common genes.

Those that form the zebrafish jaw are analogous to those that form a bone in the human inner ear.

Crump spent another year tracking down the gene that's responsible for the mutation and the nucleotides that make up that gene.

Fish raised without the gene not only failed to develop proper jawbones but also lacked the muscles that normally attach to the bone, and had poorly developed nerves connecting the area to the brain.

It turns out that the gene regulates the formation of a certain type of embryonic cell, called endodermal cells, which in turn help direct the development of other tissue involved in facial development.

Crump determined that in zebrafish the endodermal cells formed tissue that acted as a kind of scaffolding for the development of bone, muscle and nerve tissue in a very focused part of its head.

Fish that lacked the gene failed to produce the endodermal cells.

"All these differences could be traced back to this piece of tissue that's missing," he said. "Having local control of development could call for more specific evolution of other parts of the body."

In humans, the work suggests that rather than a single "master gene" that governs facial appearance, the way a person looks is determined by many genes, each directing the formation of bone, muscle and nerves in a relatively small and specific part of the head. The same kind of model could also apply in other parts of the body.

"I think it will be a good model," Crump said. "The basic building blocks are going to be the same."

The research also helps further understand the "cross-talk" that goes on between different kinds of tissue. That cross-cellular communication is seen as a key factor in organ development.

Crump hopes that the research eventually will help scientists better understand not only normal development but also how some people end up with malformations in the head and face, and that it will point to new ways to detect potential problems.

"It will give us another piece of information," he said. "It gives us directions to look in."

CAPTION(S):

Gage Crump, a postdoctoral researcher at the University of Oregon, uses tropical fish to learn about the formation of facial structures. Thomas Boyd / The Register-Guard Researcher Gage Crump inspects a small tank of zebrafish that he uses in his research that has revealed a genetic mechanism for the development of faces.