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Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Minireview cung cấp cho các bạn kiến thức về ngành y đề tài: IDivergence in cis-regulatory networks: taking the ‘species’ out of crossspecies analysis | Minireview Divergence in c s-regulatory networks taking the species out of crossspecies analysis Robert P Zinzen and Eileen EM Furlong Address European Molecular Biology Laboratory D-69117 Heidelberg Germany. Correspondence Eileen EM Furlong. Email furlong@embl.de Published 4 November 2008 Genome B ology 2008 9 240 doi l0.ll86 gb-2008-9-ll-240 The electronic version of this article is the complete one and can be found online at http genomebiology.com 2008 9 11 240 2008 BioMed Central Ltd Abstract Many essential transcription factors have conserved roles in regulating biological programs yet their genomic occupancy can diverge significantly. A new study demonstrates that such variations are primarily due to c s-regulatory sequences rather than differences between the regulators or nuclear environments. Genetic studies in a range of organisms reveal that essential transcription factors TFs tend not only to be conserved in sequence but also in function. For example the NKx2.5 TFs are essential for heart development in species as diverse as mice 1 zebrafish 2 Xenopus 3 humans 4 and Drosophila 5 . At a structural level the DNA-binding domains of many orthologous TFs are highly similar over large evolutionary distances allowing them to bind to identical DNA motifs. In fact cross-species experiments demonstrate that ortholo-gous TFs can regulate the same target genes and even rescue some mutant phenotypes 6 7 . It is thus reasonable to assume that conserved TFs which lead to the development and maintenance of orthologous tissues 8 regulate conserved sets of downstream target genes as part of conserved gene-regulatory networks. It therefore came as a surprise when recent studies on DNA binding of the TFs Zeste among Drosophila species 9 and Ste12 and Tec1 across yeast species 10 indicated that individual binding events turn over rapidly during evolution. A similar discovery has been made for liver-specific TFs among vertebrates 11 . Mouse and human hepatocytes have a .
