A DEVELOPMENTALLY-REGULATED POSITION EFFECT AT A TELOMERIC LOCUS IN TRYPANOSOMA-BRUCEI
A DEVELOPMENTALLY-REGULATED POSITION EFFECT AT A TELOMERIC LOCUS IN TRYPANOSOMA-BRUCEI
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DOI：
10.1016/0092-8674(95)90095-0
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发表时间：
1995-11-17
期刊：
影响因子：
64.5
通讯作者：
CROSS, GAM
中科院分区：
文献类型：
--
作者：
HORN, D;CROSS, GAM
布氏锥虫在哺乳动物宿主中经历抗原变异。这可以通过激活和灭活端粒变异体特异性表面糖蛋白基因（vsg）来实现。在原环（昆虫中肠阶段）细胞中，Vsg不表达。调节vsg表达位点（ES）转录的机制尚不清楚。在这里，我们表明，从三个不同的启动子的转录被抑制时，他们被插入在一个转录沉默端粒近端基因座在血流形成的细胞。这种位置效应是稳定的和可遗传的。只有从ES启动子转录被压抑在procycliccell。观察到的位置效应和启动子特异性的发育调控表明，这些现象反映了调控vsg表达的机制。
Trypanosoma brucei undergoes antigenic variation in the mammalian host. This can be achieved by activation and inactivation of telomeric variant-specific surface glycoprotein genes (vsg). In procyclic (insect midgut stage) cells, Vsg is not expressed. The mechanisms that regulate transcription of vsg expression sites (ESs) are unknown. Here we demonstrate that transcription from three different promoters was repressed when they were inserted at a transcriptionally silent telomere-proximal locus in bloodstream-form cells. This position effect was stable and heritable. Only transcription from an ES promoter was repressed in procyclic cells. The observed position effect and the promoter-specific developmental regulation suggest that these phenomena reflect the mechanisms that regulate vsg expression.