Name: Yun-Bo Shi
Address: Building 18T, Rm 106, Unit of Molecular
Morphogenesis, Laboratory of Molecular Embryology, NICHD/NIH
Phone no.: 301-402-1004
Fax no.: 301-402-1323
E-mail address: shi@helix.nih.gov
Research interests: Thyroid Hormone Regulation of Cell Death and Survival during Amphibian Metamorphosis.
We 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.
Patterton, D., Hayes, W. P., and Shi, Y.-B. (1995) Transcriptional activation of the matrix metalloproteinase gene stromelysin-3 coincides with thyroid hormone-induced cell death during frog metamorphosis. Dev. Biol. 167, 252-262.
Stolow, M. A., and Shi, Y.-B. (1995) Xenopus sonic hedgehog as a potential morphogen during embryogenesis and thyroid hormone-dependent metamorphosis. Nuc. Acids Res. 23, 2555-2562.
Wong, J., and Shi, Y.-B. (1995) Coordinated regulation of and transcriptional activation by Xenopus thyroid hormone and retinoid X receptors. J. Biol. Chem. 270, 18479-18483.
Wong, J., Shi, Y.-B., and Wolffe, A. P. (1995) A role for nucleosome assembly in both silencing and activation of the Xenopus TRbA gene by the thyroid hormone receptor. Genes and Development, 9, 2696-2711.
Shi, Y.-B., Wong, J., Puzianowska-Kuznicka, M. (1996) Thyroid hormone receptors: Mechanisms of transcriptional regulation and roles during frog development. J. Biomedical Science. 3, 307-318.
Ishizuya-Oka, A., Ueda, S. , and Shi, Y.-B. (1996) Transient expression of stromelysin-3 mRNA in the amphibian small intestine during metamorphosis. Cell Tissue Res. 283, 325-329.
Shi, Y.-B., Wang, R.-X., and Shi, Y.-F. (1996) Apoptosis: The molecular mechanism. Life Sciences 8 (3), 8-12.
Shi, Y.-B. (1996) Thyroid hormone-regulated early and late genes during amphibian metamorphosis. In Metamorphosis: Post-embryonic reprogramming of gene expression in amphibian and insect cells.(Eds. L. I. Gilbert, J. R. Tata, and B. G. Atkinson). pp. 505-538. Academic Press, New York.
Puzianowska-Kuznicka, M., and Shi, Y.-B. (1996) Nuclear factor I as a potential regulator during post-embryonic organ development. J.Biol. Chem. 271, 6273-6282.
Stolow, M. A., Bauzon, D. D., Li, J., Sedgwick, T., Liang, V. C.-T., Sang, Q. A., and Shi, Y.-B. (1996) Identification and characterization of a novel collagenase in Xenopus laevis: Possible roles during frog development.Mol. Biol. of the Cell. 7, 1471-1483.
Shi, Y.-B., and Ishizuya-Oka, A. (1996) Biphasic intestinal development in amphibians: Embryogenesis and remodeling during metamorphosis.Current Topics in Developmental Biology. 32, 205-235.
Puzianowska-Kuznicka, M., Wong, J., Kanamori, A., and Shi, Y.-B. (1996) Functional characterization of a mutant thyroid hormone receptor in Xenopus laevis J. Biol. Chem. 271, 33394-33403.
Shi, Y.-B., Wong, J., Puzianowska-Kuznicka, M., and Stolow, M. A. (1996) Tadpole competence and tissue-specific temporal regulation of amphibian metamorphosis: Roles of thyroid hormone and its receptors. BioEssays 18, 391-399.
Yun-Bo Shi