概括
在Xenopus laevis的染色体子单元中含有核糖体RNA片段. 活跃转录的胚胎细胞比不活跃的成年细胞显示出较少的核糖体基因组,表明基因包装差异.
科学领域:
- 分子生物学分子生物学
- 遗传学 遗传学 是一个
- 细胞生物学 细胞生物学
背景情况:
- 染色体结构在调节基因表达方面起着至关重要的作用.
- 核糖体RNA (rRNA) 基因对蛋白质合成至关重要,并且在特定的染色体区域内组织.
研究的目的:
- 为了研究来自Xenopus laevis细胞的染色质子单元的组成.
- 为了确定这些子单元内的核糖体RNA基因 (rRNA) cistron表现的程度.
- 为了比较活跃转录的rRNAcistron含量与转录沉默的细胞.
主要方法:
- 核酸杂交被用来分析微型菌核酶衍生的染色体子单元中的DNA片段.
- 染色素从培养的胚胎Xenopus laevis细胞和成年红细胞中分离出来.
主要成果:
- 染色体子单元包含与200个基对DNA片段相关联的28S,18S和5S核糖体RNA片段.
- 活跃转录胚胎细胞的子单元含有原生DNA中发现的rRNAcystron的70-74%.
- 不活跃的成年红细胞的子单元含有约90%的rRNAcistrons.
结论:
- 染色体包装在Xenopus laevis的活跃转录和转录沉默的核糖体RNA基因之间有所不同.
- 不同的rRNA基因的可访问性和包装性可能有助于调节核糖体RNA合成.
相关概念视频
DNA as a Genetic Template
Two structural features of the DNA molecule provide a basis for the mechanisms of heredity: the four nucleotide bases and its double-stranded nature. The Watson-Crick model of double-helical DNA structure, proposed in 1952, drew heavily upon the X-ray crystallography work of researchers Rosalind Franklin and Maurice Wilkins. Watson, Crick, and Wilkins jointly received the Nobel Prize in Physiology or Medicine for their work in 1962. Franklin was, controversially, excluded from the prize for...
Nucleosome Remodeling
Nucleosomes are the basic units of chromatin compaction. Each nucleosome consists of the DNA bound tightly around a histone core, which makes the DNA inaccessible to DNA binding proteins such as DNA polymerase and RNA polymerase. Hence, the fundamental problem is to ensure access to DNA when appropriate, despite the compact and protective chromatin structure.
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Nucleosome remodeling complex
Eukaryotic cells have specialized enzymes called ATP-dependent nucleosome remodeling enzymes. These enzymes...
Duplication of Chromatin Structure
The process of chromosome duplication during cell division requires genome-wide disruption and re-assembly of chromatin. The chromatin structure must be accurately inherited, reassembled, and maintained in the daughter cells to ensure lineage propagation.
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
Mechanical Protein Function
Proteins perform many mechanical functions in a cell. These proteins can be classified into two general categories- proteins that generate mechanical forces and proteins that are subjected to mechanical forces. Proteins providing mechanical support to the structure of the cell, such as keratin, are subjected to mechanical force, whereas proteins involved in cell movement and transport of molecules across cell membranes, such as an ion pump, are examples of generating mechanical force.
Cryo-electron Microscopy
Conventional electron microscopy (EM) involves dehydration, fixation, and staining of biological samples, which distorts the native state of biological molecules and results in several artifacts. Also, the high-energy electron beam damages the sample and makes it difficult to obtain high-resolution images. These issues can be addressed using cryo-EM, which uses frozen samples and gentler electron beams. The technique was developed by Jacques Dubochet, Joachim Frank, and Richard Henderson, for...
Methods of Nuclear Reprogramming
Nuclear reprogramming is a process of transforming one cell type into an unrelated cell type by epigenetic changes that alter the cell’s original gene expression pattern. Such epigenetic changes force cells to express a different set of genes, which play a significant role in inducing transformation into other cell types. Nuclear reprogramming offers applications in reproductive cloning for livestock propagation and regenerative medicine — developing patient-specific cells for injury repair.


