Genetics and Development Faculty Research
My scientific research projects focus on the molecular mechanism underlying temperature-dependent sex determination in reptiles. The goal of the work underway in my laboratory is to identify regulatory proteins that are selectively activated by temperature during the temperature-sensitive period for sexual development in the snapping turtle, Chelydra serpentina. The general hypothesis is that one of the transcription factors involved in the gene transcription cascade that leads to the determination of sex in turtles is particularly temperature sensitive and therefore is functional at one temperature, either male-producing or female-producing, and not at the other temperature. The mechanism underlying temperature regulation of sex determination in reptiles is a fascinating biological problem by itself but is may also have broader importance. The mechanism driving this phenomenon may represent a novel mechanism for gene regulation in animals, which might also operate in the control of other developmental or physiological processes. Work in my laboratory also has major implications for animal conservation in the face of global climate change.
Broadly described, my research interests focus on the various pathways that bacteria use to sort proteins to their appropriate destinations. In particular, I am interested in the molecular mechanisms by which some proteins are delivered to and assembled within the bacterial outer membrane (OM) while others are secreted from the bacterial cell altogether. Since the OM acts as a barrier to toxic compounds, formation of this compartment is critically important for bacteria to survive in harsh environments like the human gut. Similarly, secreted proteins are often involved in establishing and maintaining bacterial infections inside animal hosts. I believe that a clearer understanding of these processes is critical for development of novel treatments to control bacterial infections.
For over 30 years, my research has focused on understanding the fundamental mechanisms that control plant cell growth and development. Within that context, my current research focuses on understanding the biological mechanisms that control cotton fiber growth and development. Most of the textile properties of cotton fiber are directly affected by the biological processes that control cell elongation and wall synthesis. My lab uses a multi-faceted approach, employing ultrastructural analysis (both light and electron microscopy), pharmacological studies and physiological investigations. Through these analyses we will identify pivotal developmental mechanisms and “windows of opportunity” that can be modified in ways that will improve the textile properties of cotton fiber and increase the economic value of US grown cotton.
Currently my lab has research interests in two areas: (1) My primary area of interest is the non-neuronal functions of LIM-homeodomain (LIM-HD) transcription factors. One reporter fusion that has been traditionally used to mark the thin gonadal sheath (see interest number 2) is lim-7, a member of the Islet subgroup of the LIM-HD transcription factor family, fused to Green Fluorescent Protein (GFP). LIM-HD proteins are evolutionarily conserved, and while much is known about the role of LIM-HD proteins in motor neurons, much less is known about its function in non-neuronal tissues. The LIM-7 LIM-HD protein is expressed in the gonadal sheath and a small tissue-specific enhancer element has been identified in its intron 1, which is necessary and sufficient for the expression of a reporter in the gonadal sheath. We are trying to understand more about the function and regulation of this protein. (2) The second interest I have is to understand the genetic signals and mechanisms necessary for cells to differentiate into a specialized tissue or organ. We are using the gonadal sheath tissue of the free-living ground-dwelling nematode Caenorhabditis elegans as a model. This simple tissue, composed of ten cells, mostly surrounds each arm of the gonad and is indispensable for fertility. We have used RNA interference to identify the genes that are necessary for the development and maintenance of this tissue.
Faculty Research: All Biology Faculty