概括
在Trypanosoma brucei (T. brucei) 中经常发生染色体重组,改变染色体大小并可能影响表面抗原基因表达. 这些变化可能会被标准遗传分析遗漏.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 寄生虫学的寄生虫学
背景情况:
- trypanosoma brucei (T. brucei) 是一个原生虫寄生虫,负责非洲试虫病.
- 变异性表面糖蛋白 (VSG) 基因切换是T. brucei.免疫逃避的一个关键机制.
- 了解染色体动力学对于破译T. brucei生物学和病变产生至关重要.
研究的目的:
- 研究T. brucei.染色体重组的发生和特征.
- 为了确定这些重新排列的频率,试管体分裂.
- 探索染色体重组与表面抗原基因表达的变化之间的潜在联系.
主要方法:
- 脉冲场梯度凝电泳 (PFGE) 用于分离大型DNA分子.
- 在不同的T. brucei分离物中分析染色体大小分布.
- 观察到的重组与表面抗原基因表达模式的相关性.
主要成果:
- 检测到T. brucei的小染色体 (200-700 kb) 的尺寸变化,每次分裂的频率为10^-5到10^-6.
- 在不同的T. brucei分离物中观察到染色体大小分布的显著变化.
- 将几种染色体重排与表面抗原基因表达的变化联系起来.
- 提供了T. brucei.中蛋白质编码基因不连续转录的证据.
结论:
- 染色体重排是T. brucei中经常发生的事件,影响染色体大小和潜在的基因表达.
- 标准分子技术可能无法检测与抗原基因切换相关的大型DNA重组.
- 基因重组可能在T. brucei. 变异表面基因表达的动态调节中发挥作用.
相关概念视频
Lampbrush Chromosomes
7.1K
In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, Rückert observed LBCs in shark egg cells and coined the term "lampbrush chromosomes" because they looked like brushes used to clean kerosene lamps.
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops...
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops...
7.1K
Polytene Chromosomes
9.3K
Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also...
9.3K
Conservative Site-specific Recombination and Phase Variation
5.7K
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
5.7K
Synteny and Evolution
2.9K
John H. Renwick first coined the term “synteny” in 1971, which refers to the genes present on the same chromosomes, even if they are not genetically linked. The species with common ancestry tend to show conserved syntenic regions. Therefore, the concept of synteny is nowadays used to describe the evolutionary relationship between species.
Around 80 million years ago, the human and mice lineages diverged from the common ancestor. During the course of evolution, the ancestral...
Around 80 million years ago, the human and mice lineages diverged from the common ancestor. During the course of evolution, the ancestral...
2.9K
Exon Recombination
3.1K
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...
Exon shuffling follows “splice frame rules.” Each exon...
3.1K
Crossing Over
6.3K
Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to allelic diversity in the newly formed daughter cells. In humans, crossing over produces genetically distinct haploid egg and sperm cells that undergo fertilization to produce unique offspring. Before cell division starts, the germ cell’s chromosome(s) undergo duplication in the S phase of the cell cycle. As the cells enter prophase I,...
6.3K


