Mishra Krishnaveni, Chopra Vivek S, Srinivasan Arumugam, Mishra Rakesh K
Centre for Cellular and Molecular Biology, Uppal Road, 500007 Hyderabad, India.
Mech Dev. 2003 Jun;120(6):681-9. doi: 10.1016/s0925-4773(03)00046-7.
Epigenetic inheritance to maintain the expression state of the genome is essential during development. In Drosophila, the cis regulatory elements, called the Polycomb Response Elements (PREs) function to mark the epigenetic cellular memory of the corresponding genomic region with the help of PcG and trxG proteins. While the PcG genes code for the repressor proteins, the trxG genes encode activator proteins. The observations that some proteins may function both as PcG and trxG member and that both these group of proteins act upon common cis elements indicate at least a partial functional overlap among these proteins. Trl-GAGA was initially identified as a trxG member but later was shown to be essential for PcG function on several PREs. In order to understand how Trl-GAGA functions in PcG context, we have looked for the interactors of this protein. We identified lola like, aka batman, as a strong interactor of GAGA factor in a yeast two-hybrid screen. lolal also interacts with polyhomeotic and, like Trl, both lolal and ph are needed for iab-7PRE mediated pairing dependent silencing of mini-white transgene. These observations suggest a possible mechanism of how Trl-GAGA plays a role in maintaining the repressed state of target genes involving lolal, which may function as a mediator to recruit PcG complexes.
表观遗传继承以维持基因组的表达状态在发育过程中至关重要。在果蝇中,称为多梳反应元件(PREs)的顺式调控元件在多梳基因家族(PcG)和三胸复合物基因家族(trxG)蛋白的帮助下,作用于标记相应基因组区域的表观遗传细胞记忆。PcG基因编码阻遏蛋白,而trxG基因编码激活蛋白。一些蛋白质可能同时作为PcG和trxG成员发挥作用,并且这两组蛋白质都作用于共同的顺式元件,这些观察结果表明这些蛋白质之间至少存在部分功能重叠。Trl-GAGA最初被鉴定为trxG成员,但后来被证明对多个PREs上的PcG功能至关重要。为了了解Trl-GAGA在PcG环境中的功能,我们寻找了该蛋白的相互作用分子。我们在酵母双杂交筛选中鉴定出类lola(又名蝙蝠侠)作为GAGA因子的强相互作用分子。lolal也与多同源蛋白相互作用,并且与Trl一样,lolal和ph都是iab-7PRE介导的mini-white转基因配对依赖性沉默所必需的。这些观察结果提示了Trl-GAGA如何通过lolal在维持靶基因抑制状态中发挥作用的一种可能机制,lolal可能作为招募PcG复合物的介质。