Leland Stanford Junior University

Roeland Nusse

Karl Willert

Irving L Weissman

Tannishtha Reya

Compositions of purified biologically active Wnt proteins are provided. Wnt proteins are found to be hydrophobic and post-translationally modified by addition of a lipid moiety at a conserved cysteine residue. Methods for isolation of Wnt utilize detergents that maintain the solubility of the modified protein.

Compositions of active WNT protein

Compositions of active Wnt protein

Mammalian progenitor or stem cells are expanded in vitro by increasing the levels of &bgr;-catenin in the cell. The expanded cells substantially maintain their original phenotype including the ability to give rise to multiple types of differentiated cells. The intracellular levels of &bgr;-catenin may be manipulated by providing exogenous &bgr;-catenin protein to the cell, or by introduction into the cell of a genetic construct encoding &bgr;-catenin. The &bgr;-catenin may be a wild-type or stabilized mutant form of the protein. Preferably the long term cell culture medium substantially lacks stromal cells and cytokines.

Growing community of inventors

Stanford, CA, United States of America

Roeland Nusse