Ruvalcaba-Salazar Omar K, del Carmen Ramírez-Estudillo Ma, Montiel-Condado Dvorak, Recillas-Targa Félix, Vargas Miguel, Hernández-Rivas Rosaura
Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Apartado Postal 14-740, 07360 México.
Mol Biochem Parasitol. 2005 Apr;140(2):183-96. doi: 10.1016/j.molbiopara.2005.01.002.
RNA polymerase II promoters in Plasmodium spp., like in most eukaryotes, have a bipartite structure. However, the identification of a functional TATA box located within the Plasmodium spp. core promoters has been difficult, mainly because of its high A+T content. Only few putative trans-acting elements have been identified in the malaria parasite genome such as a gene orthologous to the TATA box binding protein (PfTBP). In this study, we demonstrate that PfTBP is part of the DNA-protein complexes formed in the kahrp and gbp-130 gene promoter regions. Supershift and footprinting assays performed with a GST-PfTBP fusion protein showed that PfTBP associates with a consensus TATA box sequence located 81 base pairs upstream of the transcription start site in the kahrp promoter region and with a TATA box-like (TGTAA) sequence at position -186 of the gbp-130 gene promoter region. Chromatin immunoprecipitation assays confirmed that native PfTBP is able to associate in vivo with both TATA box elements. This is the first study that reports the identification of cis-acting sequences (TATAA and TGTAA) and their corresponding trans-acting (PfTBP) factor in P. falciparum.
与大多数真核生物一样，疟原虫属中的RNA聚合酶II启动子具有二分结构。然而，在疟原虫属核心启动子中鉴定功能性TATA框一直很困难，主要是因为其A+T含量很高。在疟原虫基因组中仅鉴定出少数推定的反式作用元件，例如与TATA框结合蛋白（PfTBP）直系同源的基因。在本研究中，我们证明PfTBP是在kahrp和gbp - 130基因启动子区域形成的DNA - 蛋白质复合物的一部分。用GST - PfTBP融合蛋白进行的超迁移和足迹分析表明，PfTBP与位于kahrp启动子区域转录起始位点上游81个碱基对处的共有TATA框序列以及gbp - 130基因启动子区域-186位置的TATA框样（TGTAA）序列相关联。染色质免疫沉淀分析证实天然PfTBP能够在体内与两个TATA框元件相关联。这是第一项报道在恶性疟原虫中鉴定顺式作用序列（TATAA和TGTAA）及其相应反式作用（PfTBP）因子 的研究。
