Wnts are secreted ligands which activate receptor-mediated signaling pathways. Vertebrate Wnts and their signaling pathways have been implicated in playing key roles in axis specification, in patterning mesoderm and the nervous system, in providing polarity to limbs, and in organogenesis. When inappropriately activated, components of the Wnt pathways may be linked to various human cancers notably colorectal cancer and melanoma. The current proposal represents a competing continuation application, to maintain funding for our work on Wnt genes and their signaling pathways in Xenopus. As the previous specific aims have largely been answered, our present proposal introduces new specific aims to address recent questions arising from this prior support. Whereas many of the previous specific aims asked embryological questions, the current focus is on Wnt signal transduction.
Aim 1 uses yeast-two hybrid screens, and mass spectroscopy analysis, to identify new components of the Wnt-1/Frizzled-1 pathway.
Aim 2 investigates the biochemistry of the distinct Wnt-5a/Frizzled-2 pathway which we discovered in the prior two project periods.
Aim 3 investigates the target genes of Wnt signaling and their functions in development. Given the high degree of conservation of the Wnt-1 signaling pathway in evolution, it is likely the results of this work in Xenopus will continue to directly apply to Wnt signaling in other vertebrates.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD027525-08A1
Application #
2852419
Study Section
Human Embryology and Development Subcommittee 1 (HED)
Program Officer
Klein, Steven
Project Start
1991-02-01
Project End
2004-06-30
Budget Start
1999-07-01
Budget End
2000-06-30
Support Year
8
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Washington
Department
Pharmacology
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
Waxman, Joshua S (2005) Regulation of the early expression patterns of the zebrafish Dishevelled-interacting proteins Dapper1 and Dapper2. Dev Dyn 233:194-200
Waxman, Joshua S; Hocking, Anne M; Stoick, Cristi L et al. (2004) Zebrafish Dapper1 and Dapper2 play distinct roles in Wnt-mediated developmental processes. Development 131:5909-21
Sheldahl, Laird C; Slusarski, Diane C; Pandur, Petra et al. (2003) Dishevelled activates Ca2+ flux, PKC, and CamKII in vertebrate embryos. J Cell Biol 161:769-77
Cheyette, Benjamin N R; Waxman, Joshua S; Miller, Jeffrey R et al. (2002) Dapper, a Dishevelled-associated antagonist of beta-catenin and JNK signaling, is required for notochord formation. Dev Cell 2:449-61
Brown, J D; Hallagan, S E; McGrew, L L et al. (2000) The maternal Xenopus beta-catenin signaling pathway, activated by frizzled homologs, induces goosecoid in a cell non-autonomous manner. Dev Growth Differ 42:347-57
Hoppler, S; Moon, R T (1998) BMP-2/-4 and Wnt-8 cooperatively pattern the Xenopus mesoderm. Mech Dev 71:119-29
McGrew, L L; Hoppler, S; Moon, R T (1997) Wnt and FGF pathways cooperatively pattern anteroposterior neural ectoderm in Xenopus. Mech Dev 69:105-14
Larabell, C A; Torres, M; Rowning, B A et al. (1997) Establishment of the dorso-ventral axis in Xenopus embryos is presaged by early asymmetries in beta-catenin that are modulated by the Wnt signaling pathway. J Cell Biol 136:1123-36
Hoppler, S; Brown, J D; Moon, R T (1996) Expression of a dominant-negative Wnt blocks induction of MyoD in Xenopus embryos. Genes Dev 10:2805-17
Cui, Y; Brown, J D; Moon, R T et al. (1995) Xwnt-8b: a maternally expressed Xenopus Wnt gene with a potential role in establishing the dorsoventral axis. Development 121:2177-86

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