来自自然形成的dsRNAs的内源性siRNAs调节小鼠卵细胞中的转录
Toshiaki Watanabe1, Yasushi Totoki, Atsushi Toyoda
1Division of Human Genetics, Department of Integrated Genetics, National Institute of Genetics, Research Organization of Information and Systems, Mishima 411-8540, Japan. toshwata@lab.nig.ac.jp
Nature
|April 12, 2008
概括
哺乳动物卵细胞利用来自自然双链RNAs (dsRNAs) 的内源性小干扰RNAs (siRNAs) 来调节基因表达和逆转移子,即使没有依赖RNA的RNA聚合酶 (RdRP) 活动.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
背景情况:
- RNA干扰 (RNAi) 是一种特定序列的基因沉默机制,涉及双链RNAs (dsRNAs).
- 内源性小干扰RNAs (siRNAs) 通常需要RNA-依赖的RNA聚合酶 (RdRP) 来实现其生物发生和功能.
- 在缺乏RdRP活性的哺乳动物中,内源性siRNAs的作用和起源在很大程度上仍未被描述.
研究的目的:
- 研究小鼠卵细胞内源性siRNAs的生物发生和功能.
- 确定哺乳动物卵细胞中小RNA的来源和调节作用.
- 在没有RdRP的情况下,阐明RNAi途径参与基因和逆转移素调节.
主要方法:
- 在成长中的小鼠卵细胞中深度测序小RNA.
- 分析小干扰RNAs (siRNAs) 和Piwi相互作用RNAs (piRNAs) 的序列和起源.
- 在Dicer和Ago2淘汰赛小鼠卵细胞中评估基因和逆转移体表达.
主要成果:
- 识别与Mili结合的丰富的piRNAs和来自逆转移子和蛋白质编码转录的siRNAs.
- 证明自然存在的dsRNAs,来自诸如反向重复和反意义转录之类的来源,产生siRNAs.
- 证据表明,Dicer或Ago2的损失导致siRNAs减少和目标转录水平增加,证实了RNAi通路的功能.
结论:
- 内源性siRNAs存在于哺乳动物卵细胞中并具有功能,调节蛋白质编码基因和逆转移体.
- 缺乏RdRP的哺乳动物有机体可以从内源的dsRNA产生功能性内源siRNA.
- 伪基因可以作为siRNAs的前体,通过RNAi促进它们的创始源mRNAs的调节.
相关概念视频
02:30siRNA - Small Interfering RNAs
Small interfering RNAs, or siRNAs, are short regulatory RNA molecules that can silence genes post-transcriptionally, as well as the transcriptional level in some cases. siRNAs are important for protecting cells against viral infections and silencing transposable genetic elements.
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
01:23RNA Interference
RNA interference (RNAi) is a process in which a small non-coding RNA molecule blocks the post-transcriptional expression of a gene by binding to its messenger RNA (mRNA) and preventing the protein from being translated.
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
02:15Experimental RNAi
RNA interference (RNAi) is a cellular mechanism that inhibits gene expression by suppressing its transcription or activating the RNA degradation process. The mechanism was discovered by Andrew Fire and Craig Mello in 1998 in plants. Today, it is observed in almost all eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. This precise cellular mechanism of gene silencing has been developed into a technique that provides an efficient way to identify and determine the...
02:57piRNA - Piwi-interacting RNAs
PIWI-interacting RNAs, or piRNAs, are the most abundant short non-coding RNAs. More than 20,000 genes have been found in humans that code for piRNAs while only 2000 genes have been found for miRNAs. piRNAs can act at the transcriptional and post-transcriptional levels and have a vital role in silencing transposable elements present in germ cells. They are also involved in epigenetic silencing and activation. Previously, they were thought to function only in germ cells but new evidence suggests...
01:23Regulation of Expression at Multiple Steps
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the addition of a...
02:39lncRNA - Long Non-coding RNAs
In humans, more than 80% of the genome gets transcribed. However, only around 2% of the genome codes for proteins. The remaining part produces non-coding RNAs which includes ribosomal RNAs, transfer RNAs, telomerase RNAs, and regulatory RNAs, among other types. A large number of regulatory non-coding RNAs have been classified into two groups depending upon their length – small non-coding RNAs, such as microRNA, which are less than 200 nucleotides in length, and long non-coding RNA (lncRNA)...