an nf-κb and slug regulatory loop active in early vertebrate mesoderm一个nf-κb和蛞蝓监管循环活跃在早期脊椎动物中胚层.pdfVIP

An NF-kB and Slug Regulatory Loop Active in Early Vertebrate Mesoderm 1 1 1 2 1 Chi Zhang , Timothy F. Carl , Evan D. Trudeau , Thomas Simmet , Michael W. Klymkowsky * 1 Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America, 2 Institute of Pharmacology of Natural Products and Clinical Pharmacology, University of Ulm, Ulm, Germany Background. In both Drosophila and the mouse, the zinc finger transcription factor Snail is required for mesoderm formation; its vertebrate paralog Slug (Snai2) appears to be required for neural crest formation in the chick and the clawed frog Xenopus laevis. Both Slug and Snail act to induce epithelial to mesenchymal transition (EMT) and to suppress apoptosis. Methodology Principle Findings. Morpholino-based loss of function studies indicate that Slug is required for the normal expression of both mesodermal and neural crest markers in X. laevis. Both phenotypes are rescued by injection of RNA encoding the anti- apoptotic protein Bcl-xL; Bcl-xL’s effects are dependent upon IkB kinase-mediated activation of the bipartite transcription factor NF-kB. NF-kB, in turn, directly up-regulates levels of Slug and Snail RNAs. Slug indirectly up-regulates levels of RNAs encoding the NF-kB subunit proteins RelA, Rel2, and Rel3, and directly down-regulates levels of the pro-apopotic Caspase-9 RNA. Conclusions/Significance. These studies reveal a Slug/Snail–NF-kB regulatory circuit, analogous to that present in the early Drosophila embryo, active during mesodermal formation in Xenopus. This is a regulatory interaction of significance both in development and in the course of inflammatory and metastatic disease. Citation: Zhang C, Carl TF, Trudeau ED, Simmet T, Klymkowsky MW (2006) An NF-kB and Slug Regulatory Loop Ac