Transcriptional Regulation of Telomeric Expression Sites and Antigenic Variation in Trypanosomes.
Transcriptional Regulation of Telomeric Expression Sites and Antigenic Variation in Trypanosomes.
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DOI：
10.2174/1389202918666170911161831
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发表时间：
2018-03
期刊：
影响因子：
2.6
通讯作者：
Stuart K
中科院分区：
文献类型：
--
作者：
Cestari I;Stuart K
布氏锥虫利用抗原变异通过周期性改变其变异表面糖蛋白（VSGs）外壳来逃避宿主抗体的清除。T.布氏杆菌编码超过2，500个VSG基因和假基因，然而它们每次仅从20个端粒表达位点（ES）之一转录一个VSG基因。VSG由RNA聚合酶I以单等位基因方式从称为ES体的核仁位点转录。VSG抗原转换通过端粒ES之间的转录转换或通过表达的VSG基因的重组而发生。VSG的表达受发育调控，其转录受表观遗传机制控制，并受端粒位置效应的影响。 在这里，我们讨论了1）端粒ES和VSG抗原转换转录的分子基础; 2）VSG单等位基因表达的现有知识; 3）磷酸肌醇途径在VSG表达和转换调控中的作用; 4）前环素和VSG基因Pol I转录的发育调控。
Trypanosoma brucei uses antigenic variation to evade the host antibody clearance by periodically changing its Variant Surface Glycoprotein (VSGs) coat. T. brucei encode over 2,500 VSG genes and pseudogenes, however they transcribe only one VSG gene at time from one of the 20 telomeric Expression Sites (ESs). VSGs are transcribed in a monoallelic fashion by RNA polymerase I from an extranucleolar site named ES body. VSG antigenic switching occurs by transcriptional switching between telomeric ESs or by recombination of the VSG gene expressed. VSG expression is developmentally regulated and its transcription is controlled by epigenetic mechanisms and influenced by a telomere position effect. Here, we discuss 1) the molecular basis underlying transcription of telomeric ESs and VSG antigenic switching; 2) the current knowledge of VSG monoallelic expression; 3) the role of inositol phosphate pathway in the regulation of VSG expression and switching; and 4) the developmental regulation of Pol I transcription of procyclin and VSG genes.