Research InterestsMolecular basis of Xenopus metamorphosis
Research AreaWe are studying the intestinal development during metamorphosis of the amphibian Xenopus laevis. The tadpole intestine is a simple tubular organ consisting of predominantly a single layer of primary epithelium. It is drastically remodeled during metamorphosis into a complex structure with multiple epithelial folds. This process involves complete degeneration of the primary epithelium through apoptosis and proliferation and differentiation of various types of adult cells. The process is entirely controlled by thyroid hormone (TH). Thus, merely by adding TH to tadpole rearing water or to the medium of intestinal organ cultures, one can induce precocious apoptosis in the primary epithelium and adult cell proliferation and differentiation. TH controls metamorphosis by regulating gene expression. We have recently isolated many TH response genes in the intestine. Our research focuses primarily on the regulation and function of these genes during intestinal remodeling. Of particular interests are genes which can alter the extracellular matrix (ECM), which plays important roles during organ development. Matrix metalloproteinases (MMPs) are important participants in the remodeling of the ECM during organogenesis. We have identified several MMP genes as TH response genes in the intestine. Among them is the stromelysin-3 gene, whose expression during metamorphosis correlates with cell death in various organs. We are interested in the spatial and temporal expression of stromelysin-3 protein and mRNA and its function in ECM modification and thus its potential role in influencing cell death vs. proliferation and differentiation. We also plan to investigate the roles of various ECM components and other MMPs during intestinal epithelial morphogenesis.
Current MembersShi, Yun-Bo (Principal Investigator/Director)
ContactInstitution: NICHD, NIH Address:
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9000 Rockville Pike
Personal Phone: 619 534 3896