Institute of Gerontology


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Judith H. Willis

Professor
jhwillis@cb.uga.edu
http://www.uga.edu/~cellbio/willis.html

University of Georgia
Athens, GA 30602
706.542.0802 (voice)
(fax)



Research Interests

Two major problems in insect physiology remain fertile areas for analysis—the genetic basis for metamorphosis and the ways chitin and cuticular proteins interact to form the diverse types of cuticle found in a single insect in different regions and at different metamorphic stages. My research program combines these two areas. We have used cuticular proteins as molecular indictors of metamorphic stages to probe the action of the two hormones that control metamorphosis. We are studying the interaction of cuticular proteins with chitin using proteins expressed in vitro and by analyses of the structure and diversity of cuticular proteins.

Past research in my laboratory has focused on cuticular proteins in the giant silk moth, Hyalophora cecropia, and their regulation by juvenoids and ecdysteroids. My students and I have shown that some cuticular proteins are used in more than a single metamorphic stage while others are stage-specific. We have isolated and characterized the genes for two cuticular proteins that are expressed in more than one stage. Studies on their regulation indicate that both transcriptional and translational controls are involved. In the hope of identifying a more tractable experimental system, I am working with hormone-responsive cell lines derived from wing imaginal discs of the Indian meal moth and of Drosophila. If similarities are found between development in vivo and in vitro, we will have an excellent model system for learning how hormones control the complex macromolecular changes that accompany metamorphosis.

We have recently learned that a novel protein domain, found in many cuticular proteins in crustaceae, arachnids and insects, is necessary and sufficient for such proteins to bind to chitin. A new research thrust is to learn how many cuticular protein genes are found in a single species and to analyze in detail their patterns of expression. Anopheles gambiae has been selected for this study because its entire genome has been sequenced. As a result, numerous fundamental questions about metamorphosis and coordination of cuticular protein gene expression are now amenable to direct analysis.