Lamiable O, Rabhi M, Peronnet F, Locker D, Decoville M
Centre de Biophysique Moléculaire, CNRS UPR 4301, conventionnée avec l'Université d'Orléans, Orléans, France.
Genesis. 2010 Apr;48(4):244-53. doi: 10.1002/dvg.20609.
Two main classes of proteins, Polycomb group (PcG) and Trithorax group (TrxG), play a key role in the regulation of homeotic genes. These proteins act in multimeric complexes to remodel chromatin. A third class of proteins named Enhancers of Trithorax and Polycomb (ETP) modulates the activity of TrxG and PcG, but their role remains largely unknown. We previously identified an HMGB-like protein, DSP1 (Dorsal Switch Protein 1), which was classified as an ETP. Preliminary studies have revealed that DSP1 is involved in multimeric complexes. Here we identify a DEAD-box RNA helicase, Rm62, as partner of DSP1 in a 250-kDa complex. Coimmunoprecipitation assays performed on embryo extracts indicate that DSP1 and Rm62 are associated in 3- to 12-h embryos. Furthermore, DSP1 and Rm62 colocalize on polytene chromosomes. Consistent with these results, a mutation in Rm62 enhances a null mutation of dsp1 and also mutations of trxG or PcG, suggesting that Rm62 has characteristics of an ETP. We show here for the first time that an RNA helicase is involved in the maintenance of homeotic genes.
两类主要蛋白质，即多梳蛋白家族（PcG）和三胸蛋白家族（TrxG），在同源异型基因的调控中起关键作用。这些蛋白质以多聚体复合物的形式发挥作用，重塑染色质。第三类蛋白质称为三胸蛋白和多梳蛋白增强子（ETP），可调节TrxG和PcG的活性，但其作用在很大程度上仍不清楚。我们之前鉴定出一种HMGB样蛋白DSP1（背侧开关蛋白1），它被归类为一种ETP。初步研究表明，DSP1参与多聚体复合物。在这里，我们鉴定出一种DEAD盒RNA解旋酶Rm62，它是250 kDa复合物中DSP1的伙伴。对胚胎提取物进行的免疫共沉淀分析表明，DSP1和Rm62在3至12小时的胚胎中相互关联。此外，DSP1和Rm62在多线染色体上共定位。与这些结果一致，Rm62中的突变增强了dsp1的无效突变以及trxG或PcG的突变，这表明Rm62具有ETP的特征。我们首次在此表明，一种RNA解旋酶参与同源异型基因的维持。
