A unique GCN5 histone acetyltransferase complex controls erythrocyte invasion and virulence in the malaria parasite Plasmodium falciparum.
A unique GCN5 histone acetyltransferase complex controls erythrocyte invasion and virulence in the malaria parasite Plasmodium falciparum.
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DOI：
10.1371/journal.ppat.1009351
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发表时间：
2021-08
期刊：
影响因子：
6.7
通讯作者：
Cui L
中科院分区：
文献类型：
--
作者：
Miao J;Wang C;Lucky AB;Liang X;Min H;Adapa SR;Jiang R;Kim K;Cui L
组蛋白乙酰转移酶GCN5相关的SAGA复合体从酵母到人类在进化上是保守的，在全球基因调控中作为一个通用的转录辅助激活因子发挥作用。在这项研究中，我们在恶性疟原虫中发现了一个分化的GCN5复合体，它包含两个植物同源结构域(PfPHD1和PfPHD2)蛋白和一个植物AP2(AP2)结构域转录因子(PfAP2-LT)。为了剖析PfGCN5复合体的功能，我们构建了PfGCN5中的溴域或PfPHD1中的PhD结构域缺失的寄生虫系。这两个缺失突变体彼此表型相近，表现为显著减少裂殖子对红细胞的侵袭，并提高性转换。这些结构域的缺失不仅导致了组蛋白H3K9乙酰化的显著减少，也导致了H3K4三甲基化的显著减少，表明这两个常染色质标记之间存在协同串扰。PfGCN5或PfPHD1中的结构域缺失严重扰乱了全球转录模式，导致超过60%的基因表达发生变化。在裂殖体阶段，这些结构域的缺失与参与红细胞入侵的裂殖子基因的特异性下调有关，其中许多裂殖子基因包含AP2-LT结合基序，并受到AP2-I和BDP1的调节，这表明这些特定因素有针对性地将PfGCN5复合体招募到入侵基因中。相反，在环阶段，PfGCN5或PfPHD1结构域的缺失扰乱了编码毒力因子PfEMP1的整个var基因家族的互斥表达模式。染色质状态与基因表达变化的相关性分析表明，这些突变体中上调和下调的基因分别与野生型寄生虫的沉默和活跃染色质状态高度相关。总的来说，PfGCN5复合体代表了一个新的HAT复合体，它具有一个独特的亚基组成，包括一个AP2转录因子，这意味着一种新的范例，可以靶向共激活复合体来调节这种低分枝原生生物中的一般和寄生虫特异性的细胞过程。在疟疾寄生虫恶性疟原虫中，基因表达的表观遗传调控在协调一般和寄生虫特异性细胞通路方面起着至关重要的作用。为了更好地了解这种寄生虫的表观遗传机制，我们研究了组蛋白乙酰转移酶GCN5在该寄生虫红细胞内发育过程中的转录调控。通过串联亲和纯化和蛋白质组学鉴定，PfGCN5相关复合体包含9个核心成分，包括两个PHD结构域蛋白(PfPHD1和PfPHD2)和一个AP2结构域转录因子，它不同于从酵母到人类进化保守的典型GCN5复合体。为了了解PfGCN5复合体的功能，我们在该复合体的两个亚基PfGCN5和PfPHD1中进行了结构域的删除。我们发现这两个缺失突变体表现出非常相似的生长表型，包括显著降低裂殖子侵袭率和提高性转换。这两个突变与组蛋白H3K9乙酰化和H3K4三甲基化显著减少有关，这导致染色质状态和基因表达的全局变化。与表型一致的是，受PfGCN5和PfPHD1基因破坏显著影响的基因包括那些参与寄生虫特异途径的基因，如入侵、毒力和性发育。综上所述，本研究提出了一种新的PfGCN5复合体模型，用于靶向共激活复合体，以调节这种低分枝寄生虫原生生物的一般和寄生虫特异性细胞过程。
The histone acetyltransferase GCN5-associated SAGA complex is evolutionarily conserved from yeast to human and functions as a general transcription co-activator in global gene regulation. In this study, we identified a divergent GCN5 complex in Plasmodium falciparum, which contains two plant homeodomain (PHD) proteins (PfPHD1 and PfPHD2) and a plant apetela2 (AP2)-domain transcription factor (PfAP2-LT). To dissect the functions of the PfGCN5 complex, we generated parasite lines with either the bromodomain in PfGCN5 or the PHD domain in PfPHD1 deleted. The two deletion mutants closely phenocopied each other, exhibiting significantly reduced merozoite invasion of erythrocytes and elevated sexual conversion. These domain deletions caused dramatic decreases not only in histone H3K9 acetylation but also in H3K4 trimethylation, indicating synergistic crosstalk between the two euchromatin marks. Domain deletion in either PfGCN5 or PfPHD1 profoundly disturbed the global transcription pattern, causing altered expression of more than 60% of the genes. At the schizont stage, these domain deletions were linked to specific down-regulation of merozoite genes involved in erythrocyte invasion, many of which contain the AP2-LT binding motif and are also regulated by AP2-I and BDP1, suggesting targeted recruitment of the PfGCN5 complex to the invasion genes by these specific factors. Conversely, at the ring stage, PfGCN5 or PfPHD1 domain deletions disrupted the mutually exclusive expression pattern of the entire var gene family, which encodes the virulent factor PfEMP1. Correlation analysis between the chromatin state and alteration of gene expression demonstrated that up- and down-regulated genes in these mutants are highly correlated with the silent and active chromatin states in the wild-type parasite, respectively. Collectively, the PfGCN5 complex represents a novel HAT complex with a unique subunit composition including an AP2 transcription factor, which signifies a new paradigm for targeting the co-activator complex to regulate general and parasite-specific cellular processes in this low-branching parasitic protist. Epigenetic regulation of gene expression plays essential roles in orchestrating the general and parasite-specific cellular pathways in the malaria parasite Plasmodium falciparum. To better understand the epigenetic mechanisms in this parasite, we characterized the histone acetyltransferase GCN5-mediated transcription regulation during intraerythrocytic development of the parasite. Using tandem affinity purification and proteomic characterization, we identified that the PfGCN5-associated complex contains nine core components, including two PHD domain proteins (PfPHD1 and PfPHD2) and an AP2-domain transcription factor, which is divergent from the canonical GCN5 complexes evolutionarily conserved from yeast to human. To understand the functions of the PfGCN5 complex, we performed domain deletions in two subunits of this complex, PfGCN5 and PfPHD1. We found that the two deletion mutants displayed very similar growth phenotypes, including significantly reduced merozoite invasion rates and elevated sexual conversion. These two mutants were associated with dramatic decreases in histone H3K9 acetylation and H3K4 trimethylation, which led to global changes in chromatin states and gene expression. Consistent with the phenotypes, genes significantly affected by the PfGCN5 and PfPHD1 gene disruption include those participating in parasite-specific pathways such as invasion, virulence, and sexual development. In conclusion, this study presents a new model of the PfGCN5 complex for targeting the co-activator complex to regulate general and parasite-specific cellular processes in this low-branching parasitic protist.
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影响因子：
9.8
作者：
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通讯作者：
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