概括
谢诺普斯·莱维斯 (Xenopus laevis) tRNA1met基因是并联重复的DNA,长度变化最小. 净化和限制酶消化证实了它们在特定DNA片段中的位置.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 在Xenopus laevis的研究中.
背景情况:
- 转移RNA基因 (tRNA1met) 对于蛋白质合成至关重要.
- 了解重复基因的组织,可以了解基因组结构.
研究的目的:
- 为了净化和表征含有Xenopus laevis中重复的tRNA1met基因的DNA.
- 研究这些基因序列的排列和异质性.
主要方法:
- 密度梯度离心 (actinomycin C1-CsCl,Ag+-Cs2SO4) 用于DNA净化. 这是一个非常简单的方法.
- 限制内核酶消化 (EcoRl,Hpa l) 用于分析DNA片段大小.
- 对DNA片段长度的分析以确定基因组织.
主要成果:
- 为tRNA1met基因丰富的部分净化DNA.
- 从tRNA2met和tRNAval基因中分离tRNA1met基因.
- 在EcoRl消化后,tRNA1met基因主要在3100个基对碎片中被发现.
- 这些碎片被Hpal进一步切割成2200 bp (含tRNA1met基因) 和700 bp碎片 (含其他tRNA基因).
- 证明了连续重复的DNA结构,长度异质性很小.
结论:
- 在Xenopus laevis中,tRNA1met基因被组织成并列重复.
- 基因组织表现出最小的长度异质性.
- 限制酶映射提供了重复基因排列的详细视图.
相关概念视频
Organization of Genes
Overview
Complementary DNA
Overview
From DNA to Protein
The flow of genetic information in cells from DNA to mRNA to protein is described by the central dogma, which states that genes specify the sequence of mRNAs, which in turn specify the sequence of amino acids making up all proteins. The decoding of one molecule to another is performed by specific proteins and RNAs. Because the information stored in DNA is so central to cellular function, it makes intuitive sense that the cell would make mRNA copies of this information for protein synthesis...
DNA-only Transposons
DNA-only transposons are called autonomous transposons since they code for the enzyme transposase that is required for the transposition mechanism. Insertion of transposons can alter gene functions in multiple ways. They can mutate the gene, alter gene expression by introducing a novel promoter or insulator sequence, introduce new splice sites, and change the mRNA transcripts produced, or remodel chromatin structure.
The donor site from where the transposon is excised is either degraded or...
The donor site from where the transposon is excised is either degraded or...
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...
Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...


