Telomeric Trans-silencing:: An epigenetic repression combining RNA silencing and heterochromatin formation
Telomeric Trans-silencing:: An epigenetic repression combining RNA silencing and heterochromatin formation
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DOI：
10.1371/journal.pgen.0030158
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发表时间：
2007-09-01
期刊：
影响因子：
4.5
通讯作者：
Ronsseray, Stephane
中科院分区：
文献类型：
--
作者：
Josse, Thibaut;Teysset, Laure;Ronsseray, Stephane
对黑腹果蝇中P元件阻遏的研究导致了端粒反式沉默效应（TSE）的发现，这是一种阻遏机制，通过该机制，插入亚端粒异染色质中的转座子或转基因（端粒相关序列或TAS）具有在雌性生殖系中反式阻遏同源转座子或位于常染色质中的转基因的能力。当沉默不完全时，TSE显示卵巢中卵室之间的杂色。在这里，我们报告，TSE显示通过减数分裂，这涉及到一个染色体外母系传递因子的表观遗传传递。我们表明，这种沉默是高度敏感的突变影响异染色质形成（Su（var）205编码异染色质蛋白1和Su（var）3-7）和重复相关的小干扰RNA（或rasiRNA）沉默途径（茄子，无家可归，阿米蒂奇，和piwi）。相比之下，TSE对影响r2d2的突变不敏感，其参与小干扰RNA（或siRNA）沉默途径，也不对参与微小RNA（或miRNA）沉默途径的loquacious中的突变敏感。这些结果，结合最近发现的与PIWI蛋白相关的TAS同源小RNA，支持了TSE涉及与异染色质形成相关的重复序列相关的小干扰RNA途径的主张，该途径被P元件增选以在其最近入侵D.黑腹果蝇基因组。因此，TSE的研究提供了对种系特异性小RNA沉默途径的遗传特性的深入了解。
The study of P-element repression in Drosophila melanogaster led to the discovery of the telomeric Trans-Silencing Effect (TSE), a repression mechanism by which a transposon or a transgene inserted in subtelomeric heterochromatin ( Telomeric Associated Sequence or TAS) has the capacity to repress in trans in the female germline, a homologous transposon, or transgene located in euchromatin. TSE shows variegation among egg chambers in ovaries when silencing is incomplete. Here, we report that TSE displays an epigenetic transmission through meiosis, which involves an extrachromosomal maternally transmitted factor. We show that this silencing is highly sensitive to mutations affecting both heterochromatin formation (Su( var) 205 encoding Heterochromatin Protein 1 and Su( var) 3-7) and the repeat-associated small interfering RNA ( or rasiRNA) silencing pathway ( aubergine, homeless, armitage, and piwi). In contrast, TSE is not sensitive to mutations affecting r2d2, which is involved in the small interfering RNA ( or siRNA) silencing pathway, nor is it sensitive to a mutation in loquacious, which is involved in the micro RNA ( or miRNA) silencing pathway. These results, taken together with the recent discovery of TAS homologous small RNAs associated to PIWI proteins, support the proposition that TSE involves a repeat-associated small interfering RNA pathway linked to heterochromatin formation, which was co-opted by the P element to establish repression of its own transposition after its recent invasion of the D. melanogaster genome. Therefore, the study of TSE provides insight into the genetic properties of a germline-specific small RNA silencing pathway.