| David Furlow |
Associate Professor
274 Briggs Hall
530.754.8609
jdfurlow (at) ucdavis (dot) edu
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Degrees:
B.S., Pennsylvania State University, 1985
Ph.D., University of Wisconsin, Madison, 1992
Post-doctoral fellow, Department of Embryology, Carnegie Institution of Washington, Baltimore MD, 1992-1997
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Teaching Interests:
Endocrinology, developmental biology, molecular biology.
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Research Interests:
Our laboratory uses modern techniques in molecular biology, biochemistry, and endocrinology to study how simple molecules such as thyroid and steroid hormones control complex developmental and reproductive processes. During early development, the embryo relies on several cues such as maternal signals from the egg, cell-cell contact, and diffusible short range molecules to direct cell fate. However, as the embryo becomes larger and establishes a circulatory system, hormonal (or endocrine) systems play a critical role in controlling many important aspects of the transition from an embryo or larva to a free living, reproducing adult.
One of the most dramatic effects of a hormone on development is that of thyroid hormone control of amphibian metamorphosis. Thyroid hormone induces changes in virtually every tissue of the organism during the transition from the aquatic, herbivorous, larval tadpole to the carnivorous, reproducing adult frog. These changes are of three basic types: the death of larval tissues (like the tail), the remodeling of larval tissues for new adult function (the intestine, brain, skin, etc.), and the growth and differentiation of tissues de novo from adult stem cells (like the limbs). We believe each of the these types of morphogenetic events is controlled by gene expression changes induced by thyroid hormone through a strongly conserved set of nuclear ligand-regulated transcription factors, the thyroid hormone receptors. We are working to understand the molecular details of metamorphosis using a three phase strategy. First, we have isolated a large number of thyroid hormone regulated genes, primarily by subtractive hybridization and homology cloning strategies. We are continuing to expand on these techniques to isolate as truly a comprehensive set of response genes as possible. Second, the regulated genes have been characterized by mapping their expression to specific cells by in situ hybridization, and by sequencing full-length cDNAs for comparison to sequence databases. Finally, and most importantly, we are in the process of analyzing the regulated gene products for function. For example, functional assays include overexpression, in vitro translation, or isolation of a regulated gene product from cell extracts for DNA binding and transcription assays if it appears to encode a transcription factor. Another important functional assay we use is the creation of transgenic Xenopus laevis. We can direct the expression of a wild-type or dominant negative proteins or a corresponding antisense RNA from integrated ubiquitous, tissue-specific, or inducible promoters. We are also keenly interested in how the thyroid hormone receptors initiate and sustain the process of metamorphosis. This set of studies includes how receptor expression is controlled, what other factors interact with them in growth versus cell death pathways, and the analysis of the promoters of induced genes in vivo by transgenic approaches. The ultimate goal of our laboratory is to delineate an entire hormone regulated gene expression cascade from the time of hormone binding to the receptor to the ultimate morphogenetic response of a given target tissue.
We are also involved in two collaborative projects:
Thyroid hormone action in developing mammalian embryos (with Catherine C. Thompson, PhD, Johns Hopkins University, Baltimore, MD)
Steroid hormone action on programming adult rat behavior (with Margaret M. McCarthy, PhD, University of Maryland Medical Center, Baltimore, MD)
In our laboratory we have experience with and routinely use the following techniques:
Recombinant DNA technology, PCR, cDNA and genomic DNA cloning, subtractive hybridization, Southern and Northern blot analysis, in situ hybridization, immunohistochemistry, Western blots, immunoprecipitation, in vitro transcription and translation, overproduction of fusion proteins, quantitative DNA binding assays, receptor-ligand binding assays, cell culture transfection assays, DNA and RNA injections into Xenopus oocytes and fertilized eggs, and transgenic Xenopus laevis production, including transgene detection (green fluorescent protein) in living embryos.
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Selected Publications:
Furlow, J.D. and D.D. Brown. 1997. Two Kinetic Classes of Thyroid Hormone Response Genes are Up-Regulated During Xenopus laevis Metamorphosis Via Evolutionarily Conserved Response Elements (submitted).
Furlow, J.D., Berry, D.L., Wang, Z. and D.D. Brown. 1997. A Set of Novel Tadpole Specific Genes Expressed Only in the Epidermis Are Down-Regulated by Thyroid Hormone During Xenopus laevis Metamorphosis. Developmental Biology 182:284-298.
Brown, D.D., Wang, Z., Furlow, J.D., Kanamori, A., Schwartzman, R.S., Remo, B.F., and A. Pinder. 1996. The Thyroid Hormone-Induced Tail Resorption Program During Xenopus laevis Metamorphosis. Proceedings of the National Academy of Sciences 93:1924-1929.
Murdoch, F.E., Byrne, L.M., Ariazi, E.A., Furlow, J.D., Meier, D.A., and J. Gorski. 1995. Estrogen Receptor Binding to DNA: Affinity for Non-Palindromic Elements from the Rat Prolactin Gene. Biochemistry 34: 9144-9150.
Brown, D.D., Wang, Z., Kanamori, A., Eliceiri, B., Furlow, J.D., and R.S. Schwartzman. 1995. Amphibian Metamorphosis: A Complex Program of Gene Expression Changes Controlled by Thyroid Hormone. Recent Progress in Hormone Research 50: 309-315.
Furlow, J.D., Murdoch, F.E., and J. Gorski. 1993. High Affinity Binding of the Estrogen Receptor to a DNA Response Element Does Not Require Homodimer Formation or Estrogen. Journal of Biological Chemistry 268:12519-12525.
Kaneko, K.J., Furlow, J.D., and J. Gorski.1993. Involvement of the Coding Sequence for the Estrogen Receptor Gene in Autologous Ligand-Dependent Down-Regulation. Molecular Endocrinology 7:879-88.
Gorski J., Furlow, J.D., Murdoch, F.E., Fritsch, M., Kaneko, K., Ying, C., and J.R. Malayer. 1993. Perturbations in the Model of Estrogen Receptor Regulation of Gene Expression. Biology of Reproduction 48:8-14. |
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