Franklin D. Costantini, PhD

Research Summary
The molecular basis of inductive interactions during mammalian embryogenesis and organogenesis; murine models of human diseases

Mutations in the mouse Fused gene interfere with normal early embryogenesis and cause axial duplications, suggesting that Fused plays an important role in embryonic axis specification and neuroectodermal development. We cloned the Fused gene (now called Axin) and found that it encodes an intracellular regulator of the Wnt signal transduction pathway. Current efforts focus on understanding the biochemical function of Axin and its paralog Axin2/Conductin, and their roles in mammalian embryogenesis and organogenesis.

Organogenesis of the kidney depends on reciprocal inductions between the epithelial ureteric bud and the surrounding mesenchymal cells, and the molecular basis of these interactions is a current area of interest. We have shown that the RET receptor tyrosine kinase is the ureteric bud receptor for an inductive signal produced by the mesenchyme, specifically the growth factor GDNF (glial cell line-derived neurotrophic factor). Current studies focus on GDNF/RET signaling mechanisms, identification of downstream genes regulated by GDNF/RET signaling, and their roles in the growth and branching morphogenesis of the ureteric bud. We have also developed transgenic mice that express green fluorescent protein (see Figure) throughout the ureteric bud, which we are using to study ureteric bud morphogenesis.

The RET gene is also a proto-oncogene involved in several inherited human cancer syndromes including Multiple Endocrine Neoplasia Type 2 (MEN2). Loss of function RET mutations in humans are associated with Hirschsprung Disease, a developmental defect in the enteric nervous system. We are also using mouse models to investigate the mechanisms by which defects in RET signaling can lead to these two disorders.

Service Activities
Director, Herbert Irving Comprehensive Cancer Center - Transgenic Animal Facility
The Transgenic Animal Facility produces transgenic and gene-targeted mice for any investigator at Columbia University.

Selected Publications

1. Jho, E.-H., Zhang, T., Domon, C., Joo, C.-K., Freund, J.-N., and Costantini, F. Wnt/b-catenin/Tcf signaling induces the transcription of Axin2, a negative regulator of the signaling pathway. Mol. Cell. Biol 22:1172-1183, 2002.

2. Watanabe, T. and Costantini, F. Real time analysis of ureteric bud branching morphogenesis in vitro. Developmental Biology 271: 98–108 , 2004.

3. Shakya, R., Watanabe, T. and Costantini, F. The role of GDNF/Ret signaling in ureteric bud cell fate and branching morphogenesis. Developmental Cell 8:65-74, 2005.

4. Chia, I. and Costantini, F. Mouse Axin and Axin2/Conductin/ proteins are functionally equivalent in vivo. Mol. Cell. Biol. 25: 4371–4376, 2005.

5. Shakya, R., Jho, E.-H., Kotka, P., Wu, Z., Kholodilov, N., Burke, R., D’Agati, V. and Costantini, F. The role of GDNF in patterning the excretory system. Developmental Biology 283: 70–84, 2005.

6. Yu, H.-M. I., Liu, B., Chiu, S.-Y., Costantini, F. and Hsu, W. Development of a novel system for spatiotemporal and lineage specific gene expression in mice. PNAS 102:8615-20, 2005.

7. Wong, A., Bogni, S., Kotke, P., de Graaff, E., D’Agati, V., Costantini, F. and Pachnis, V. Phosphotyrosine 1062 is critical for the in vivo activity of the Ret9 receptor tyrosine kinase isoform. Mol. Cell. Biol., in press, 2005.

1. Signal Transduction in Vertebrate Embryogenesis
This project concerns the role of Axin and Axin2/Conductin in Wnt signal transduction during mouse embryogenesis.
National Institute of Child Health and Human Development

2. Molecular Virology: Project II: The role of the RET proto-oncogene in development and cancer"
This component of a Program Project (P.I. Richard Axel) concerns the role of the RET receptor tyrosine kinase in the development of the peripheral nervous system, and the generation of mouse models of multiple endocrine neoplasia. The project is a collaboration with Vassilis Pachnis at NIMR in London.
National Cancer Institute

3. Molecular Events in Urogenital Development: Project III: Reciprocal Inductive Interactions in Kidney Development
This component of a Program Project (P.I. Qais-Al-Awqati) concerns the genes and inductive signals that regulate branching morphogenesis of the ureteric bud during kidney development.
National Institute of Diabetes and Digestive and Kidney Diseases

4. Recessive mutations that disrupt development of the mouse embryo
The purpose of this project (a collaboration with Kathryn Anderson and Elizabeth Lacy at Memorial Sloan-Kettering Cancer Center) is to screen for new ENU-induced mutations affecting renal organogenesis in the mouse.
National Institute of Child Health and Human Development