相关实验视频
Updated: Jul 21, 2026

12:02
Transient Gene Expression in Tobacco using Gibson Assembly and the Gene Gun
Published on: April 18, 2014
概括
研究人员创建了一个质体体内转录系统,以研究菜和Euglena gracilis中的转移RNA (tRNA) 基因表达. 这个系统成功地转录和处理了特定的tRNA基因,揭示了关键的调节性DNA序列.
科学领域:
- 分子生物学分子生物学
- 植物科学 植物科学
- 遗传学 是一个遗传学.
背景情况:
- 叶绿体拥有自己的遗传物质和转录机制,与核不同.
- 了解质细胞基因表达,特别是tRNA合成,对于理解细胞器功能至关重要.
- 以前的研究已经在叶绿体基因组中确定了tRNA基因,但需要体外转录系统进行详细分析.
研究的目的:
- 开发和表征一个功能性的质细胞在体外转录系统.
- 为了研究从菜和Euglena gracilis质体中特定的tRNA基因的转录和处理.
- 为了确定参与质细胞tRNA基因转录启动和处理的调节性DNA序列.
主要方法:
- 使用菜和Euglena gracilis提取物开发一种质体体内转录系统.
- 使用修改后的DNA模板转录特定的tRNA基因 (trn).
- 用于转录识别和处理确认的RNA指纹分析.
- 在菜trnM2位点的侧面序列中构建和分析删除突变.
主要成果:
- 在体外系统成功转录了菜 (trnM2,trnV1,trnl1) 和Euglena gracilis (trnV1-trnN1-trnR1-trnL1集群) 的tRNA基因.
- 确定了正确处理的转录,包括tRNAMetm,tRNAlle1和tRNALeu.
- 在CCA添加到成熟的tRNA中证实了质体3'核样转移酶活性.
- 位于菜trnM2位点上游 -56至 -85之间的DNA序列对于最大转录而不是处理至关重要.
结论:
- 已建立的质体体内转录系统对于研究tRNA基因表达是有效的.
- 特定的上游DNA序列在调节质细胞tRNA基因转录启动方面发挥着关键作用.
- 参与tRNA转录的叶绿体RNA聚合酶与负责rRNA转录的 RNA聚合酶不同.
相关概念视频
Transfer RNA Synthesis
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Riboswitches
Riboswitches are non-coding mRNA domains that regulate the transcription and translation of downstream genes without the help of proteins. Riboswitches bind directly to a metabolite and can form unique stem-loop or hairpin structures in response to the amount of the metabolite present. They have two distinct regions – a metabolite-binding aptamer and an expression platform.
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
The aptamer has high specificity for a particular metabolite which allows riboswitches to specifically regulate...
Protein Transport to the Stroma
Chloroplasts are triple membrane structures with an outer membrane, an inner membrane, and a thylakoid membrane, each containing distinct metabolite transporters, membrane translocons, and enzymes. Appropriate sorting and translocating these proteins to their correct membrane systems is essential for chloroplast function.
Protein complexes called the translocon of the outer chloroplast membrane or TOC complex, and the translocon of the inner chloroplast membrane or TIC complex mediate the...
Protein complexes called the translocon of the outer chloroplast membrane or TOC complex, and the translocon of the inner chloroplast membrane or TIC complex mediate the...
Protein Transport to the Outer Chloroplast Membrane
Chloroplast outer membrane proteins encoded by the nucleus are synthesized in the cytosol. Soon after synthesis, they bind cytosolic factors such as 14-3-3 protein and the Hsp70 chaperones that keep these precursors in an unfolded state until their translocation.
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.
Transfer RNA Synthesis
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Protein Transport to the Inner Chloroplast Membrane
Proteins targeted to the inner chloroplast membrane, or plastid proteins, are transported by two general pathways: the stop-transfer and the re-insertion or post-import pathways. Most plastid proteins carry N-terminal transit sequences and internal import sequences targeting it to the specific chloroplast subcompartment. Proteins targeted by the stop-transfer pathway have internal hydrophobic sequences that inhibit their translocation into the stroma. As a result, these precursors are arrested...

