Plasmodium falciparum: Preinitiation complex occupancy of active and inactive promoters during erythrocytic stage
Plasmodium falciparum: Preinitiation complex occupancy of active and inactive promoters during erythrocytic stage
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DOI：
10.1016/j.exppara.2008.09.016
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发表时间：
2009-01-01
影响因子：
2.1
通讯作者：
Lopez-Estrano, Carlos
中科院分区：
文献类型：
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作者：
Gopalakrishnan, Anusha M.;Nyindodo, Lilian A.;Lopez-Estrano, Carlos
超过80%的恶性疟原虫基因在寄生虫的生命周期中受到发育调节，大多数基因以“及时”的方式表达。然而，基因调控的分子机制仍然知之甚少。对一种恶性疟原虫基因组的分析表明，这种寄生虫编码的转录因子似乎相对较少，与其他真核生物中的转录因子同源。我们用染色质免疫沉淀法(ChIP)研究了PfTBP和PfTFIIE与疟原虫阶段特异性启动子的相互作用。我们的结果表明，在活性和非活性的红细胞表达启动子中，PftBP和PfTFIIE与它们的同源序列结合。此外，由于还检测到PfTBP与编码区和3‘末端区域的相互作用，Tf的占有率似乎延伸到启动子区域之外。在红细胞无性生殖阶段无效的CSP和Pfs25基因上未检测到PfTBP或PfTFIIE相互作用。更重要的是。PfTBP和PfTFIIE结合似乎与组蛋白3和/或4乙酰化无关，提示组蛋白乙酰化可能不是PfTBP或PfTFIIE启动子相互作用的先决条件。基于我们的观察，我们得出结论，含有PfTBP/PfTFIIE的预起始复合体(PIC)将以一种独立于组蛋白乙酰化的方式预先组装在所有红细胞表达的基因的启动子上，这为“稳定”模型提供了支持。与真核基因调控的经典模型相反，PIC与疟原虫启动子的相互作用独立于转录活性和染色质乙酰化导致PIC组装的概念。(C)2008 Elsevier Inc.保留所有权利。
Over 80% of Plasmodium falciparum genes are developmentally regulated during the parasite's life cycle with most genes expressed in a "just in time" fashion. However, the molecular mechanisms of gene regulation are still poorly understood. Analysis of A falciparum genome shows that the parasite appears to encode relatively few transcription factors homologous to those in other eukaryotes. We used Chromatin immunoprecipitation (Chip) to study interaction of PfTBP and PfTFIIE with stage specific Plasmodium promoters. Our results indicate that PftBP and PfTFIIE are bound to their cognate sequence in active and inactive erythrocytic-expressed promoters. In addition, TF occupancy appears to extend beyond the promoter regions, since PfTBP interaction with the coding and 3' end regions was also detected. No PfTBP or PfTFIIE interaction was detected on csp and pfs25 genes which are not active during the erythrocytic asexual stage. Furthermore. PfTBP and PfTFIIE binding did not appear to correlate with histone 3 and/or 4 acetylation, suggesting that histone acetylation may not be a prerequisite for PfTBP or PfTFIIE promoter interaction. Based on our observations we concluded that the PfTBP/PfTFIIE-containing preinitiation complex (PIC) would be preassembled on promoters of all erythrocytic-expressed genes in a fashion independent of histone acetylation, providing support for the "poised" model. Contrary to the classical model of eukaryotic gene regulation, PIC interaction with Plasmodium promoters occurred independent of transcriptional activity and to the notion that chromatin acetylation leads to PIC assembly. (C) 2008 Elsevier Inc. All rights reserved.