Gender	Male
E-mail	david.sassoon@mssm.edu
Education and Training	Ph.D., Columbia University
	B.A., University of California
	Postdoctoral Training, Pasteur Institute
Awards	1997 Kenner Fellow Award The American Heart Association
	1996 Established Scientist Award American Heart Association-NYC affiliate
	1994 Hirschl Scholar Award
	1991 Recipient of The Marcus Singer Award at Woods Hole
	1989 American Cancer Society Postdoctoral Fellow
	1986 Muscular Dystrophy Association Postdoctoral Fellow

Education and Training	Ph.D., Columbia University
	B.A., University of California
	Postdoctoral Training, Pasteur Institute

Molecular mechanisms controlling embryonic patterning and cell differentiation: Applications to cancer cell biology

The overall interest of our research is to elucidate the cellular and molecular mechanisms that control patterning during embryogenesis in vertebrates. It is anticipated that the understanding of normal developmental mechanisms controlling cell growth and differentiation will have a strong bearing upon our understanding of cancer where normal regulatory control is lost or missregulated.

1] We have recently reported the cloning and characterization of a large multidomain Zn-finger protein called Pw1. This was a result of an effort to identify early regulators of the mesodermal/skeletal muscle lineage in murine development. PW1 is a nuclear protein expressed at high levels in muscle, liver, CNS (and pituitary) and the immune system. Differential display for myc/ p53 induced apoptosis identified a fragment of 500bp with perfect identity to Pw1. Pw1/cmyc co-expression results in apoptosis in fibroblasts, thus PW1 may be a downstream target (direct or indirect) of p53. We have recently observed that PW1 associates with tumor-necrosis-factor associated factor 2 (TRAF2). This gene is a key transducer in several cytokine pathways that lead to NFkB activation which has been recently demonstrated to inhibit cell death. Thus, PW1 appears to play a role in both cell death and cell survival. We see that PW1 is required for TRAF2 activation of NFkB. We are currently exploring its role during mouse embryogenesis and during cell differentiation.

2] We have been pursuing the role of the Wnt family of growth factors on the development of the female reproductive tract. Studies using heterografting techniques reveal that Wnt gene expression governs the proper patterning of the uterus and underlies the epithelial-mesenchymal interactions that lead to correct smooth muscle formation. Recent observations suggest that the DES syndrome in women is due to a misregulation of Wnt-7a. This misregulation ultimately leads to tumorigenesis in the reproductive tract.

3] Engrailed-2 is a homeogene expressed in the CNS and in the muscles of the jaw. We are examining what role En-2 plays in this skeletal muscle and how the expression of En-2 is specifically directed to one muscle. By generating mice that have ectopic muscle expression of En-2 and mice carrying defined regions of the EN-2 regulatory elements, we hope to provide a general picture as to how patterning is achieved during skeletal myogenesis.

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Miller C, Degenhardt K, Sassoon D. Fetal exposure to DES results in de-regulation of Wnt7a during uterine morphogenesis. Nat Genet 1998 Nov; 20(3): 228-30.

Relaix F, Wei XJ, Wu X, Sassoon D. Peg3/Pw1 is an imprinted gene involved in the TNF-NFkappaB signal transduction pathway. Nat Genet 1998 Mar; 18(3): 287-91.

Kitajewski J, Sassoon D. The emergence of molecular gynecology: homeobox and Wnt genes in the female reproductive tract. Bioessays 2000; 22(10): 902-10.

Relaix F, Wei X, Li W, Pan J, Lin Y, Bowtell DD, Sassoon D, Wu X. Pw1/Peg3 is a potential cell death mediator and cooperates with Siah1a in p53-mediated apoptosis. Proc Natl Acad Sci U S A 2000; 97(5): 2105-10.

Degenhardt K, Sassoon D. A role for Engrailed-2 in determination of skeletal muscle physiologic properties. Dev Biol 2001; 231(1): 175-89.

Rentschler S, Vaidya DM, Tamaddon H, Degenhardt K, Sassoon D, Morley GE, Jalife J, Fishman GI. Visualization and functional characterization of the developing murine cardiac conduction system. Development 2001; 128(10): 1785-92.

Polekhina G, House CM, Traficante N, Mackay JP, Relaix F, Sassoon D, Parker MW, Bowtell DD. Siah ubiquitin ligase is structurally related to TRAF and modulates TNF-alpha signaling. Nat Struct Biol 2002; 9(1): 68-75.

Habelhah H, Frew I, Laine A, Janes P, Relaix F, Sassoon D, Bowtell D, Ronai Z. Siah2 is a regulator of TRAF2 stability. EMBO J 2002;.

Degenhardt K, Rentschler S, Fishman G, Sassoon D. Cellular and cis-regulation of En-2 expression in the mandibular arch. Mech Dev 2002; 111(1-2): 125-36.

Coletti D, Yang E, Marazzi G, Sassoon D. TNFalpha inhibits skeletal myogenesis through a PW1-dependent pathway by recruitment of caspase pathways. EMBO J 2002; 21(4): 631-42.