Natural variation of the amino-terminal glutamine-rich domain in Drosophila argonaute2 is not associated with developmental defects.
Natural variation of the amino-terminal glutamine-rich domain in Drosophila argonaute2 is not associated with developmental defects.
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DOI：
10.1371/journal.pone.0015264
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发表时间：
2010-12-17
期刊：
影响因子：
3.7
通讯作者：
Müller HA
中科院分区：
文献类型：
--
作者：
Hain D;Bettencourt BR;Okamura K;Csorba T;Meyer W;Jin Z;Biggerstaff J;Siomi H;Hutvagner G;Lai EC;Welte M;Müller HA
果蝇 argonaute2 (ago2) 基因在 siRNA 介导的 RNA 沉默途径中发挥着重要作用。与哺乳动物的 Argonaute 蛋白不同，果蝇蛋白具有不寻常的氨基末端结构域，主要由富含谷氨酰胺的重复序列 (GRR) 的多个副本组成。我们在这里报告，ago2 基因座产生一个替代转录本，该转录本编码一个没有这个氨基末端结构域的推定的短亚型。先前报道的几种 ago2 突变为无效等位基因，仅消除了含有 GRR 的长亚型的表达。先前对脱落 (dop) 突变的分析表明，GRR 拷贝数的变化会导致 RNAi 和胚胎发育缺陷。然而，我们发现dop突变在基因上补充了ago2的转录无效等位基因，并且具有变异GRR拷贝数的ago2等位基因支持正常发育。此外，我们还发现，当 GRR 拷贝数改变时，胚胎中中央 RNAi 机制 RISC（RNA 诱导沉默复合物）的组装不会受到损害。事实上，我们发现 GRR 拷贝数在天然黑腹果蝇群体以及实验室菌株中变化很大。最后，虽然许多其他昆虫共享广泛的、富含谷氨酰胺的 Ago2 氨基末端结构域，但其一级序列在物种之间存在巨大差异。我们的数据表明，GRR 变异并不调节 Ago2 的基本功能，并且 Ago2 的氨基末端结构域经历了快速进化。
The Drosophila argonaute2 (ago2) gene plays a major role in siRNA mediated RNA silencing pathways. Unlike mammalian Argonaute proteins, the Drosophila protein has an unusual amino-terminal domain made up largely of multiple copies of glutamine-rich repeats (GRRs). We report here that the ago2 locus produces an alternative transcript that encodes a putative short isoform without this amino-terminal domain. Several ago2 mutations previously reported to be null alleles only abolish expression of the long, GRR-containing isoform. Analysis of drop out (dop) mutations had previously suggested that variations in GRR copy number result in defects in RNAi and embryonic development. However, we find that dop mutations genetically complement transcript-null alleles of ago2 and that ago2 alleles with variant GRR copy numbers support normal development. In addition, we show that the assembly of the central RNAi machinery, the RISC (RNA induced silencing complex), is unimpaired in embryos when GRR copy number is altered. In fact, we find that GRR copy number is highly variable in natural D. melanogaster populations as well as in laboratory strains. Finally, while many other insects share an extensive, glutamine-rich Ago2 amino-terminal domain, its primary sequence varies drastically between species. Our data indicate that GRR variation does not modulate an essential function of Ago2 and that the amino-terminal domain of Ago2 is subject to rapid evolution.
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影响因子：
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种群基因组学：果蝇果蝇中多态性和差异的全基因组分析。
影响因子：
9.8
作者：
Begun, David J.;Holloway, Alisha K.;Stevens, Kristian;Hillier, LaDeana W.;Poh, Yu-Ping;Hahn, Matthew W.;Nista, Phillip M.;Jones, Corbin D.;Kern, Andrew D.;Dewey, Colin N.;Pachter, Lior;Myers, Eugene;Langley, Charles H.
通讯作者：
Langley, Charles H.
影响因子：
4.5
作者：
Meyer WJ;Schreiber S;Guo Y;Volkmann T;Welte MA;Müller HA
通讯作者：
Müller HA