通过微RNAs对基因表达的转录控制
Basel Khraiwesh1, M Asif Arif, Gotelinde I Seumel
1Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestrasse 1, 79104 Freiburg, Germany.
Cell
|January 21, 2010
概括
微RNAs (miRNAs) 通常在转录后使基因沉默. 在中,一种特定的突变揭示了miRNAs也通过DNA甲基化启动表观遗传沉默,这取决于miRNA和目标RNA水平.
科学领域:
- 植物生物学 植物生物学
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
- 分子生物学分子生物学
背景情况:
- 微RNAs (miRNAs) 是小型RNAs,在植物和动物中通过转录后调节基因表达.
- 虽然已知小干扰RNAs (siRNAs) 诱导转录基因沉默,但miRNAs在这个过程中的作用尚不太清楚.
研究的目的:
- 研究微RNAs (miRNAs) 在转录基因调节中的作用.
- 阐明miRNAs可能影响表观遗传沉默的机制.
主要方法:
- 使用的突变物Physcomitrella patens缺乏DICER-LIKE1b基因.
- 分析miRNA成熟,目标RNA裂变,转录水平和DNA甲基化模式.
- 用激素治疗野生类型的,以观察通路诱导.
主要成果:
- 没有DICER-LIKE1b的突变体显示出正常的miRNA成熟,但取消了目标RNA裂变,导致转录水平降低.
- 这些突变者积累了miRNA:目标RNA复合体,并表现出目标基因的高甲基化,导致基因沉默.
- 观察到的表观遗传沉默途径也在激素治疗后在野生类型的中被诱导.
结论:
- 微RNAs (miRNAs) 可以通过DNA甲基化启动表观遗传沉默,独立于它们的正规转录后作用.
- 这种表观遗传沉默途径的启动取决于miRNA与其点RNA之间的比率.
- 这一发现揭示了植物中miRNAs对基因调节的一种新层.
相关概念视频
MicroRNAs
MicroRNA (miRNA) are short, regulatory RNA transcribed from introns—non-coding regions of a gene—or intergenic regions—stretches of DNA present between genes. Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA ends...
MicroRNAs
MicroRNA (miRNA) are short, regulatory RNA transcribed from introns (non-coding regions of a gene) or intergenic regions (stretches of DNA present between genes). Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself, forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA...
MicroRNAs
MicroRNA (miRNA) are short, regulatory RNA transcribed from introns—non-coding regions of a gene—or intergenic regions—stretches of DNA present between genes. Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA ends...
Regulation of Expression Occurs at Multiple Steps
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Regulation of Expression Occurs at Multiple Steps
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Regulation 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...


