SMCHD1将染色体组合并协助在不活跃的X上形成超级结构
Chen-Yu Wang1, Teddy Jégu1, Hsueh-Ping Chu1
1Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA; Department of Genetics, Harvard Medical School, Boston, MA, USA.
Cell
|June 12, 2018
概括
含有1 (SMCHD1) 蛋白质的染色体结构维护链域重新配置非活跃的X染色体. SMCHD1通过减弱隐藏的Xi架构层来促进Xist的传播,从而创建一个没有隔间的结构.
科学领域:
- 基因组学
- 表观遗传学
- 分子生物学
背景情况:
- 哺乳动物的染色体具有A/B区和拓相关的域 (TAD).
- 不活跃的X (Xi) 染色体表现出一种独特的形状,缺乏明显的区间或TAD.
- 在剂量补偿过程中,X染色体的无活化是一个关键过程.
研究的目的:
- 研究含有1 (SMCHD1) 的染色体结构维护链域在X染色体失活中的作用.
- 阐明SMCHD1如何影响非活性X染色体的结构重组.
- 了解SMCHD1,Xist扩散和Xi上的染色体结构之间的关系.
主要方法:
- 在X染色体失活的背景下对建筑蛋白SMCHD1的探索.
- 在Xi形成过程中对染色体区和TAD组织的分析.
- 在SMCHD1操作时评估Xist扩散和异色沉默.
主要成果:
- 在Xist的早期传播过程中,A/B区块融合为S1和S2区块.
- SMCHD1与S1/S2区块结合,将它们合并为一个没有区块的架构.
- TAD在Xi上持续存在,但被减弱;SMCHD1的切除增强了TAD并损害了Xist的扩散和沉默.
结论:
- 在建立非活性X染色体的独特结构方面,SMCHD1起着至关重要的作用.
- 为Xi折叠提出了一种阶段模型,涉及到隐藏的架构层的SMCHD1-介导衰减.
- SMCHD1对于有效的Xist扩散和维护Xi上的异色沉默至关重要.
相关概念视频
Chromosome Structure
26.6K
A functional eukaryotic chromosome must contain three elements: a centromere, telomeres, and numerous origins of replication.
The centromere is a DNA sequence that links sister chromatids. This is also where kinetochores, protein complexes to which spindle microtubules attach, are constructed after the chromosome is replicated. The kinetochores allow the spindle microtubules to move the chromosomes within the cell during cell division.
Telomeres consist of non-coding repetitive nucleotide...
The centromere is a DNA sequence that links sister chromatids. This is also where kinetochores, protein complexes to which spindle microtubules attach, are constructed after the chromosome is replicated. The kinetochores allow the spindle microtubules to move the chromosomes within the cell during cell division.
Telomeres consist of non-coding repetitive nucleotide...
26.6K
Chromosome Structure
6.3K
6.3K
Polytene Chromosomes
11.0K
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...
11.0K
Lampbrush Chromosomes
8.7K
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...
8.7K
Chromosome Replication
10.7K
Before a cell can divide, it must accurately replicate all of its chromosomes, including the DNA and its associated histone and non-histone proteins. This process begins at numerous origins of replication during the S phase of the cell cycle in each of a cell’s chromosomes simultaneously. Certain nucleotides can act as origins of replication, but these sequences are not well defined - especially in complex, multi-cellular, eukaryotic species. The length of DNA that spans an origin...
10.7K
Inheritance of Chromatin Structures
7.6K
Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the differential gene expression pattern to maintain cell lineage, position-effect variegation, dosage compensation, and maintenance of chromatin structures such as telomeres and centromeres. For example, the structure and location of the centromere on chromosomes are epigenetically inherited. Its functionality is not dictated or ensured by the underlying...
7.6K


