Professor Analyzes Nuclear Receptors In Bee Genome

Her piece of the puzzle -- analyzing the nuclear hormone receptors found in the bee genome -- also appears in the current issue of Insect Molecular Biology.

The honey bee was chosen to have its genome sequenced because of its dual importance to agriculture and medicine. The well-known pollination activities of honey bees add billions of dollars of value to U.S. crops every year, but bees are also used in the laboratory to study issues related to human health such as immunity, longevity and diseases of the X chromosome. In addition, brain scientists are interested in the honey bee's complex social life and their ability to communicate the location of flowers to other members of the hive.

Fahrbach, Reynolds Professor of Developmental Neuroscience, and her co-researchers at Wake Forest and the University of Illinois, searched the genome sequence to find all of the nuclear receptors encoded in the bee genome. They found that the same nuclear receptors that control the development of the nervous system during the early stages of a bee's life are expressed in certain, highly plastic regions of the adult bee brain where they appear to serve a similar function of regulating brain growth.

Nuclear receptors, a family of DNA-binding proteins found only in animals, regulate many aspects of development and reproduction, Fahrbach said. In humans, for example, the receptors for estrogen and testosterone are members of this family of DNA-binding proteins.

These findings shed some light on the role nuclear receptors play in the development of adult specific bee behaviors, not just in early development or reproduction.

The researchers in Fahrbach's lab also made another discovery that surprised them.

"We expected the bee to have the same set of nuclear receptors as the fruit fly because both species are insects that share a life history of metamorphosis," she said.

But, she found a gene in the bee genome that is not found in the fly. In humans, the gene is critical for normal development of the eye. Although Fahrbach does not yet know the function of the gene in the bee, the first studies show that the protein encoded by this gene is found only in the bee's developing compound eye.

Fahrbach focuses on the molecular structure of the bee brain and possible connections between hormones and behavior.

"We use the honey bee as our model system, because some regions of the bee brain grow larger as a bee gains experience flying outside of the hive to flowers," she said. "What we learn about how the little bee brain functions is almost guaranteed to tell us more about other, bigger brains."