VSG switching in Trypanosoma brucei: antigenic variation analysed using RNAi in the absence of immune selection.
VSG switching in Trypanosoma brucei: antigenic variation analysed using RNAi in the absence of immune selection.
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Brucei锥虫中的VSG转换：在没有免疫选择的情况下，使用RNAi分析了抗原变异。
DOI：
10.1111/j.1365-2958.2005.04795.x
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发表时间：
2005-09
影响因子：
3.6
通讯作者：
Rudenko, G
中科院分区：
文献类型：
--
作者：
Aitcheson, N;Talbot, S;Shapiro, J;Hughes, K;Adkin, C;Butt, T;Sheader, K;Rudenko, G
布鲁氏锥虫依靠其变异的表面糖蛋白(VSG)外壳的抗原性变异生存。我们证明使用VSG RNAi代替免疫系统来选择开关变体，可以在体外有效地研究VSG开关。与预测抑制Vsg合成后立即转换的模型相反，VsgRNAi不能诱导转换，而是以每个分裂10−4的速率发生转换。我们发现了一个高度可重复性的VSG激活层次，它似乎能够重置，因此在12个实验中，超过一半的开关事件是到两个VSG中的一个。我们利用VSG活性表达位点(ES)中的标记基因，根据开关机制来表征开关克隆。Ess之间的转录开关是首选的转换机制，因此在布氏锥虫427中鉴定的17个Ess中，至少有10个在体外可以发挥功能。我们可以通过在存在对活性ES的药物选择的情况下，通过诱导VSG RNAi来特异性地选择DNA重排介导的开关。大多数优先激活的VSG可以被多种机制激活。这种基于VSG RNAi的程序为完全在体外分析非洲锥虫的VSG转换提供了一种快速而有力的手段。
Trypanosoma brucei relies on antigenic variation of its Variant Surface Glycoprotein (VSG) coat for survival. We show that VSG switching can be efficiently studied in vitro using VSG RNAi in place of an immune system to select for switch variants. Contrary to models predicting an instant switch after inhibition of VSG synthesis, switching was not induced by VSG RNAi and occurred at a rate of 10−4 per division. We find a highly reproducible hierarchy of VSG activation which appears to be capable of resetting, whereby more than half of the switch events over 12 experiments were to one of two VSGs. We characterised switched clones according to switch mechanism using marker genes in the active VSG expression site (ES). Transcriptional switches between ESs were the preferred switching mechanism, whereby at least 10 of the 17 ESs identified in T. brucei 427 can be functionally active in vitro. We could specifically select for switches mediated by DNA rearrangements by inducing VSG RNAi in the presence of drug selection for the active ES. Most of the preferentially activated VSGs could be activated by multiple mechanisms. This VSG RNAi based procedure provides a rapid and powerful means for analysing VSG switching in African trypanosomes entirely in vitro.
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影响因子：
2.4
作者：
BARRY, JD
通讯作者：
BARRY, JD
影响因子：
14.9
作者：
CAMPBELL, DA;VANBREE, MP;BOOTHROYD, JC
通讯作者：
BOOTHROYD, JC
影响因子：
2.1
作者：
CAPBERN, A;GIROUD, C;MATTERN, P
通讯作者：
MATTERN, P
影响因子：
64.8
作者：
Freitas-Junior, LH;Bottius, E;Scherf, A
通讯作者：
Scherf, A
影响因子：
11.4
作者：
CHUNG, HMM;SHEA, C;VANDERPLOEG, LHT
通讯作者：
VANDERPLOEG, LHT