Cell Biology Section, LRB, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
To gain insight into the mechanism by which Gli-similar 2 (Glis2) regulates transcription, we performed yeast-two hybrid cDNA library screening using Glis2 as bait. This screening identified beta-catenin as a potential Glis2-interacting protein. Mammalian two-hybrid, co-immunoprecipitation, and GST-pulldown analyses supported the interaction between Glis2 and beta-catenin. Pulldown analyses with several Glis2 deletion mutants indicated that the 1st zinc finger motif of Glis2 is critical for its interaction with beta-catenin, while the armadillo repeats of beta-catenin are important in its interaction with Glis2. Reporter analyses showed that Glis2 represses T-cell factor (TCF)-mediated transcriptional activation. In addition, Glis2 represses the expression of the TCF target gene cyclin D1. Our results indicate that Glis2 interacts with beta-catenin and suggest that Glis2 functions as a negative modulator of beta-catenin/TCF-mediated transcription.