A conserved region of engrailed, shared among all en-, gsc-, Nk1-, Nk2- and msh-class homeoproteins, mediates active transcriptional repression in vivo.
A conserved region of engrailed, shared among all en-, gsc-, Nk1-, Nk2- and msh-class homeoproteins, mediates active transcriptional repression in vivo.
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发表时间：
1996-10
期刊：
影响因子：
4.6
通讯作者：
Sheryl T. Smith;J. B. Jaynes
中科院分区：
文献类型：
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作者：
Sheryl T. Smith;J. B. Jaynes
被包裹的同源蛋白在培养细胞和体内都是显性作用或“活性”转录抑制因子。当通过同源域交换重新定位到内源性 fushi tarazu 基因 (ftz) 时，它会主动抑制它，从而产生 ftz 突变表型。我们使用这种体内抑制测定绘制了 engrailed 的功能区域。除了在细胞培养测定中鉴定出的含有活性抑制结构域的区域（K. Han 和 J. L. Manley (1993) EMBO J. 12, 2723-2733）外，我们发现两个进化上保守的区域有助于活性。其中一个不位于 HD 侧翼的蛋白对于体内抑制活性尤其重要。我们发现该结构域不仅存在于所有 engrailed 类同源蛋白中，而且还存在于其他几个类的所有已知成员中，包括 goosecoid、Nk1、Nk2 和 msh。因此engrailed在体内的主动抑制功能依赖于同源盒基因超家族进化早期建立的高度保守的相互作用。我们使用救援转基因进一步表明，广泛保守的体内抑制结构域是胚胎中 engrailed 正常功能所必需的。
The engrailed homeoprotein is a dominantly acting or 'active' transcriptional repressor both in cultured cells and in vivo. When retargeted via a homeodomain swap to the endogenous fushi tarazu gene (ftz), it actively represses it, resulting in a ftz mutant phenocopy. We have mapped functional regions of engrailed using this in vivo repression assay. In addition to a region containing an active repression domain identified in cell culture assays (K. Han and J. L. Manley (1993) EMBO J. 12, 2723-2733), we find that two evolutionarily conserved regions contribute to activity. The one of these that does not flank the HD is particularly crucial to repression activity in vivo. We find that this domain is present not only in all engrailed-class homeoproteins but also in all known members of several other classes, including goosecoid, Nk1, Nk2 and msh. Thus engrailed's active repression function in vivo is dependent on a highly conserved interaction that was established early in the evolution of the homeobox gene superfamily. We further show using rescue transgenes that the widely conserved in vivo repression domain is required for the normal function of engrailed in the embryo.