HOX4 genes encode transcription factors with potential auto‐ and cross‐regulatory capacities.
HOX4 genes encode transcription factors with potential auto‐ and cross‐regulatory capacities.
复制标题
HOX4 基因编码具有潜在自动和交叉调节能力的转录因子。
作者：
Vincenzo Zappavigna;A. Renucci;Juan;Gilbert Urier;Cesare Peschle;Denis Duboule
我们在含有HOX4C启动子的基因组区域寻找了几个HOX4复合同源蛋白在人类HOX4C和HOX4D基因之间的结合。HOX4C、HOX4D和HOX-4.3同源蛋白与一个在系统发育上高度保守的DNA片段结合，该片段位于该基因间隔区的近端，包含这些HOX4蛋白的多个结合部位。通过共转染实验，我们发现这个内源DNA序列可以介导HOX4D和HOX4C蛋白的反式激活，并且这种作用需要存在与TaT相关的结合位点。相比之下，Hox-4.3蛋白无法激活，可以抑制与另外两种蛋白一起观察到的激活。这些结果表明，HOX4D和HOX4C基因是真正的序列特异性转录因子，并表明，就像在果蝇中一样，这些基因之间的交叉调节相互作用可能是它们正确表达的关键。
We have looked for the binding of several HOX4 complex homeoproteins in the genomic region containing the HOX4C promoter, between the human HOX4C and HOX4D genes. The HOX4C, HOX4D and Hox‐4.3 homeoproteins bind to a phylogenetically highly conserved DNA fragment, which is located in the proximal part of this intergenic region and contains multiple binding sites for these HOX4 proteins. Using cotransfection experiments, we show that this endogenous DNA sequence can mediate transactivation by the HOX4D and HOX4C proteins and that this effect requires the presence of TAAT‐related binding sites. The Hox‐4.3 protein, in contrast, is unable to activate and can repress the activation observed with the two other proteins. These results show that the HOX4D and HOX4C genes are genuine sequence‐specific transcription factors and suggest that, as in Drosophila, cross‐regulatory interactions between these genes might be essential for their proper expression.