Our laboratory studies molecular and cellular mechanisms of pattern formation in Xenopus embryos. We are interested to learn how developmental polarity is acquired and how cells differentiate and assemble into tissues in the vertebrate embryo. Areas of primary interest include localized cytoplasmic determinants of dorsoventral axis formation and anteroposterior neural patterning. Our group also studies the developmental role for Wnts, extracellular signaling factors related to the proto-oncogene Wnt1 protein.
Wnt signaling is deregulated in many breast tumors, colon carcinomas and melanomas. Despite the importance of Wnts in embryogenesis and in cancer, Wnt signal transduction had not been completely defined. Genetic studies in Drosophila identified frizzled, dishevelled, shaggy/zeste-white3 (GSK3),and armadillo (beta-catenin) as essential components of the 'canonical' Wnt signal transduction. Moreover, Wnts may also be involved in controlling tissue and cell polarity through additional pathways that involve novel molecular components. We use a variety of approaches such as RNA microinjections in the frog Xenopus laevis to identify new gene products that are involved in Wnt signaling and in embryonic pattern formation. Our previous work demonstrated the structural and functional conservation of the Wnt pathway in vertebrates, discovered the synergy between Wnts and TGFb signaling, and elucidated the essential role for the homeobox gene Siamois in Spemann organizer formation. Future studies will be directed towards further understanding of Wnt signaling during normal and malignant processes.