beta-Catenin expression enhances generation of mature thymocytes.

T cell factor (TCF)-1 is a T-cell-specific transcription factor that is expressed at all stages of T cell development. Deletion of the TCF-1 gene leads to an early block in thymocyte maturation precluding the study of its role at late stages and during positive selection of T cells. In this report we show that beta-catenin, a central effector in the Wnt-TCF-1 signaling pathway, regulates late stages of T cell development. Specifically, transgenic expression of beta-catenin enhances generation of mature thymocytes. Interestingly, CD8-expressing mature thymocytes were affected to a greater extent than CD4-expressing cells. These data suggest that the Wnt-beta-catenin-TCF-1 signaling pathway plays a role during late stages of T cell development.