P. Elaine Roberts

Professor of Entomology

B.A., Biology, Western Michigan University, 1967, Kalamazoo, Michigan
Ph.D., Cell Biology, University of Illinois, 1976, Urbana, Illinois

Research Interests

We are currently studying juvenile hormone (JH) regulation of gene expression. In the two striped grasshopper, Melanoplus bivittatus, JH stimulates vitellogenin synthesis by the fat body. We have isolated several intracellular proteins that bind JH. Such proteins may serve as carriers or degradative enzymes and might be confused with the JH receptor. We have published a new means of detection of JH-binding proteins after they have been purified, electrophoresed, and transferred to glass fiber filters. Once the proteins are on glass fiber filter, they may be cut out and sequenced. The amino acid sequences of these proteins will allow isolation of their genes and will thereby provide a means of finding when and in what tissues these genes are expressed. To confirm receptor action, we are cloning the vitellogenin gene by using a vitellogenin gene probe from a related acridid, the African migratory locust. Once we have sequences upstream from the gene, the JH-binding proteins will be tested for their abilities to regulate gene expression by binding to upstream sequences. Further protein biochemistry of the putative JH receptor is also in progress.

A second project in this laboratory addresses the effect of juvenile hormone or the inhibitor of JH synthesis, precocene, on migration and reproductive status of the Russian wheat aphid (RWA). Experiments are in progress to determinie whether application of juvenile hormone analogs can induce the production of alate aphids in a nonmigratory population. Such hormonal manipulation might be used to control aphid populations by causing them to migrate at a time of year when they would be unlikely to survive. Alteration of hormone levels is also being tested as a means of producing reproductive male and female aphids. All RWAs thus far identified in the United States reproduce by parthenogenesis. Reproductive males and females would facilitate gene mapping and studies on the genetics of RWA.

Selected Recent Publications

Winder, B.S. and Roberts, P.E. 1992. Characterization of the proteins from Melanoplus bivittatus that bind juvenile hormone and a refined CFDA photolabeling technique. International Journal of Biochemistry 24, 1435-1446.

Jefferies, L.S. and Roberts, P.E. 1990. A new method of detecting hormone-binding proteins electroblotted onto glass fiber filter: juvenile hormone-binding proteins from grasshopper hemolymph. Journal of Steroid Biochemistry 35, 449-455.

Shirk, P.D., O'Brachta, D.A., Roberts, P.E. and Handler, A.M. 1988. Sex- specific selection using chimeric genes: Applications to sterile insect release. In Biotechnology and Crop Protection, P. A. Hedin, J. J. Menn, and R. Hollingworth, Eds., American Chemical Society Books, Washington, DC., pp. 135-146.

Roberts, P.E. and Jefferies, L.S. 1986. The grasshopper a model for the analysis of juvenile hormone delivery to chromatin acceptor sites. Archives in Insect Biochemistry and Physiology Supplement 1, 7-23.

Roberts, P.E. 1985. Characterization of juvenile hormone binding by components of locust hemolymph. Archives of Insect Biochemistry and Physiology 2, 351-365.