Knockdown of Selenocysteine-Specific Elongation Factor in Amblyomma maculatum Alters the Pathogen Burden of Rickettsia parkeri with Epigenetic Control by the Sin3 Histone Deacetylase Corepressor Complex
Knockdown of Selenocysteine-Specific Elongation Factor in Amblyomma maculatum Alters the Pathogen Burden of Rickettsia parkeri with Epigenetic Control by the Sin3 Histone Deacetylase Corepressor Complex
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DOI：
10.1371/journal.pone.0082012
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发表时间：
2013-11-25
期刊：
影响因子：
3.7
通讯作者：
Karim, Shahid
中科院分区：
文献类型：
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作者：
Adamson, Steven W.;Browning, Rebecca E.;Karim, Shahid
硒代半胱氨酸是第21种天然氨基酸。硒蛋白具有多种功能，许多功能尚未确定，但它们通常与抗氧化活性相关。硒代半胱氨酸掺入新生多肽链中重新编码TGA终止密码子，并且该过程取决于包括硒代半胱氨酸延伸因子（SEF）在内的许多必需因子。SEF的转录表达在整个血餐中蜱中肠没有显着变化，但在唾液腺下降到20%，在快食期结束。由于硒蛋白的翻译需要这种专门的延伸因子，我们靶向该基因敲除的RNAi获得的作用硒蛋白在蜱生理学的全局视图。我们发现在蜱虫充血和胚胎发生没有显着差异，但在蜱唾液中没有检测到抗氧化能力。研究了硒蛋白在红球藻中的转录谱。感染parkeri的斑花钝眼蜱表现出硒蛋白M和过氧化氢酶活性下降，硒蛋白O、硒蛋白S和硒蛋白T活性升高。此外，病原体负荷显着改变，在SEF敲低。然后，我们通过RNA-seq确定了SEF敲低的全球影响，并绘制了分泌基因表达的巨大变化，这可能是Sin 3组蛋白去乙酰化酶辅阻遏物复合物下调的结果。
Selenocysteine is the 21st naturally-occurring amino acid. Selenoproteins have diverse functions and many remain uncharacterized, but they are typically associated with antioxidant activity. The incorporation of selenocysteine into the nascent polypeptide chain recodes the TGA stop codon and this process depends upon a number of essential factors including the selenocysteine elongation factor (SEF). The transcriptional expression of SEF did not change significantly in tick midguts throughout the blood meal, but decreased in salivary glands to 20% at the end of the fast feeding phase. Since selenoprotein translation requires this specialized elongation factor, we targeted this gene for knockdown by RNAi to gain a global view of the role selenoproteins play in tick physiology. We found no significant differences in tick engorgement and embryogenesis but detected no antioxidant capacity in tick saliva. The transcriptional profile of selenoproteins in R. parkeri-infected Amblyomma maculatum revealed declined activity of selenoprotein M and catalase and increased activity of selenoprotein O, selenoprotein S, and selenoprotein T. Furthermore, the pathogen burden was significantly altered in SEF-knockdowns. We then determined the global impact of SEF-knockdown by RNA-seq, and mapped huge shifts in secretory gene expression that could be the result of downregulation of the Sin3 histone deacetylase corepressor complex.