This movie shows that preadipocytes transfected with Wnt do not differentiate. However, when Wnt is not present, the cells differentiate and store fat in lipid droplets (stained red). The animation was created by C. Cain with micrographs kindly provided by Ormond MacDougald.
For more information, see S. E. Ross et al. published in Science. To learn how the Wnt signaling pathway works, explore the Wnt/b-Catenin Pathway in the Connections Maps at Science's STKE.
R. Moon, Wnt/b-Catenin Pathway. Science's STKE (Connections Maps), http://stke.sciencemag.org/cgi/cm/CMP_5533. [Canonical Pathway]
Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882