David S. Durica
Professor Emeritus of Biology
Ph.D., University of Connecticut
M.S., University of Connecticut
B.A., Clark University
Bizzell Library 430
As a geneticist, I have an interest in the evolution of genes and how genes assume different and varied functions within developmental programs. We are currently characterizing members of a widely studied gene family, the nuclear receptor superfamily. This family of genes encodes transcription factors- under the influence of a hormone (or hormone-like) molecule these factors bind to DNA and regulate gene activity.
The invertebrate steroid hormone ecdysone is critical for growth in arthropods. Studies in insect systems have shown that ecdysone signaling, through nuclear receptor interactions, program the expression of genes critical to insect molting and metamorphosis. Unlike many insects, which terminate growth when they emerge as adults, growth in crustaceans must be regulated in concert with reproduction, as well as with a specialized type of growth easily studied in crustaceans, limb regeneration. We have isolated the genes encoding the components of the crustacean ecdysteroid receptor and have examined the expression pattern of these nuclear receptors during molt and reproductive cycles, and in regenerating limbs. How a "common" hormonal signal might modulate these varied physiological events is unclear, but different variants of the receptors have been identified, which have different physical properties relative to DNA and hormone binding. We also know the receptors are present on DNA, even when circulating hormone levels are low.
We have recently shown that interfering with receptor signaling disrupts the earliest stages of limb regeneration- blocking cell division. We are now using next generation sequencing technologies to identify genes expressed in normal tissues, and in tissues subject to knockdown of receptor expression. We are hopeful that knowledge of the types and amounts of receptors present at different stages of growth and regeneration, coupled with targeted knock down of receptor function, will be able to allow us to identify putative receptor target genes in different adult tissues subject to hormonal control.