The dorsal‐related immunity factor, Dif, is a sequence‐specific trans‐activator of Drosophila Cecropin gene expression.
The dorsal‐related immunity factor, Dif, is a sequence‐specific trans‐activator of Drosophila Cecropin gene expression.
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背侧相关免疫因子 Dif 是果蝇天蚕素基因表达的序列特异性反式激活因子。
作者：
U. Petersen;Gunnel Bjorklund;Y. Tony;Ipl;Y. Engstrom
Rel家族转录因子的新成员，背相关免疫因子Dif，最近被克隆，并被认为参与调节果蝇的免疫反应。尽管其被分类为Rel家族成员，但Dif cDNA编码的产物先前尚未被证明是转录因子。我们现在提供的证据表明，在共转染试验中，Dif基因产物反式激活果蝇抗菌肽A1基因。反式激活需要一个40 bp的上游元件，包括昆虫κ B样基序。将kappa B样基序5 ′-GGGGATTTTT的二聚体插入到最小启动子中，可通过Dif实现高水平的报告基因表达，而该基序的几种突变形式的多聚体未被激活，证明了Dif的序列特异性。Dif的完全反式激活需要蛋白质的C末端部分。背侧形态原（dl）也可以激活天蚕素A1启动子，但程度较低，序列特异性较低。在共转染试验中，Dif和dl的同时过表达揭示了dl对Dif反式激活具有显性负效应。这项研究确定了Dif是一种序列特异性转录因子，可能是果蝇免疫反应的关键激活因子。
A new member of the Rel family of transcription factors, the dorsal‐related immunity factor, Dif, was recently cloned and suggested to be involved in regulating the immune response in Drosophila. Despite its classification as a Rel family member, the Dif cDNA‐encoded product has not been proven previously to be a transcription factor. We now present evidence that the Dif gene product trans‐activates the Drosophila Cecropin A1 gene in co‐transfection assays. The transactivation requires a 40 bp upstream element including an insect kappa B‐like motif. A dimer of the kappa B‐like motif 5′‐GGGGATTTTT inserted into a minimal promoter conferred high levels of reporter gene expression by Dif, while a multimer of several mutated versions of this motif was not activated, demonstrating the sequence specificity of Dif. Full trans‐activation by Dif requires the C‐terminal part of the protein. The morphogen dorsal (dl) can also activate the Cecropin A1 promoter, but to a lesser extent and in a less sequence‐specific manner than Dif. Simultaneous overexpression of Dif and dl in co‐transfection assays revealed that dl possesses a dominant negative effect on Dif transactivation. This study establishes that Dif is a sequence‐specific transcription factor and is probably a key activator of the immune response in Drosophila.
影响因子：
4
作者：
Y. Ip;M. Levine
通讯作者：
Y. Ip;M. Levine
果蝇形态发生素背侧的选择性核转运可以通过涉及跨膜蛋白 Toll 和蛋白激酶 A 的信号通路建立。
影响因子：
10.5
作者：
Norris,JL;Manley,JL
通讯作者：
Manley,JL
影响因子：
2.9
作者：
BLAKE, MS;JOHNSTON, KH;GOTSCHLICH, EC
通讯作者：
GOTSCHLICH, EC