XB-ART-6165Curr Biol November 19, 2002; 12 (22): 1941-5.
Lef-1 and Tcf-3 transcription factors mediate tissue-specific Wnt signaling during Xenopus development.
Wnt signaling functions repeatedly during embryonic development to induce different but specific responses. What molecular mechanisms ensure that Wnt signaling triggers the correct tissue-specific response in different tissues? Early Xenopus development is an ideal model for addressing this fundamental question, since there is a dramatic change in the response to Wnt signaling at the onset of zygotic gene transcription: Wnt signaling components encoded by maternal mRNA establish the dorsal embryonic axis; zygotically expressed Xwnt-8 causes almost the opposite, by promoting ventral and lateral and restricting dorsal mesodermal development. Although Wnt signaling can function through different signal transduction cascades, the same beta-catenin-dependent, canonical Wnt signal transduction pathway mediates Wnt signaling at both stages of Xenopus development. Here we show that, while the function of the transcription factor XTcf-3 is required for early Wnt signaling to establish the dorsal embryonic axis, closely related XLef-1 is required for Wnt signaling to pattern the mesoderm after the onset of zygotic transcription. Our results show for the first time that different transcription factors of the Lef/Tcf family function in different tissues to bring about tissue-specific responses downstream of canonical Wnt signaling.
PubMed ID: 12445388
Article link: Curr Biol
Species referenced: Xenopus laevis
Genes referenced: lef1
Morpholinos: lef1 MO1