The architecture of variant surface glycoprotein gene expression sites in Trypanosoma brucei
The architecture of variant surface glycoprotein gene expression sites in Trypanosoma brucei
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DOI：
10.1016/s0166-6851(02)00092-0
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发表时间：
2002-07-01
影响因子：
1.5
通讯作者：
Rudenko, G
中科院分区：
文献类型：
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作者：
Berriman, M;Hall, N;Rudenko, G
布鲁氏锥虫通过在不同的表面糖蛋白(VSG)基因之间切换来逃避免疫系统。活性VSG基因在大约20个端粒表达位点(Ess)中的一个转录。已有研究推测ES基因多态性在宿主适应中起作用。为了更深入地了解ES的结构，我们已经确定了细菌人工的完整序列！含有三个ES及其侧翼区域DNA的染色体(BAC)。ES相关基因(ESAG)在序列和数量上存在差异。ESAG 6和ESAG 7编码转铁蛋白受体亚单位，是目前已测序的ESAG中唯一具有功能性拷贝的ESAG。包含VO2 ES序列的BAC克隆包括大约一半的330kb“中间”染色体。这条中间染色体与T brucei 927第一染色体左侧端粒的广泛相似性表明，这一先前未见的中等大小的染色体可能是由于百万碱基染色体的断裂而产生的。意想不到的序列保守，包括假基因。表明多个ES可能是通过相对较新的单个ES扩增而产生的。(C)2002 Elsevier Science B.V.保留所有权利。
Trypanosoma brucei evades the immune system by switching between Variant Surface Glycoprotein (VSG) genes. The active VSG gene is transcribed in one of approximately 20 telomeric expression sites (ESs). It has been postulated that ES polymorphism plays a role in host adaptation. To gain more insight into ES architecture, we have determined the complete sequence of Bacterial Artificial! Chromosomes (BACs) containing DNA from three ESs and their flanking regions. There was variation in the order and number of ES-associated genes (ESAGs). ESAGs 6 and 7, encoding transferrin receptor subunits, are the only ESAGs with functional copies in every ES that has been sequenced until now. A BAC clone containing the VO2 ES sequences comprised approximately half of a 330 kb 'intermediate' chromosome. The extensive similarity between this intermediate chromosome and the left telomere of T brucei 927 chromosome I, suggests that this previously uncharacterised intermediate size class of chromosomes could have arisen from breakage of megabase chromosomes. Unexpected conservation of sequences, including pseudogenes. indicates that the multiple ESs could have arisen through a relatively recent amplification of a single ES. (C) 2002 Elsevier Science B.V. All rights reserved.