MED1 IDR 乙化重组了转录预启动复合体,重新连接了 3D 染色体相互作用,并重新编程了基因表达
bioRxiv : the preprint server for biology
|April 2, 2024
概括
MED1乙化通过协调RNA聚合酶II预启动复合体组合和染色体组织来调节基因表达. 非可乙化MED1通过重组复合体和未折叠的染色体来增强细胞生长和基因表达.
科学领域:
- 分子生物学分子生物学
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
- 癌症生物学 癌症生物学
背景情况:
- 细胞转录调节是复杂的,其失调与癌症等疾病有关.
- 调解器复合体,特别是MED1,通过组装预启动复合体 (PIC) 和影响3D染色体组织,在协调转录方面发挥着至关重要的作用.
- 在ER阳性乳腺癌 (ER+BC) 中,MED1与雌激素受体α (ER) 功能有关.
研究的目的:
- 阐明MED1是如何协调RNA聚合酶II (Pol II) PIC组合和3D染色体组织的.
- 研究MED1乙化对调节其在ER+BC细胞中的功能的作用.
主要方法:
- 在其内在无序区域 (IDR) 中研究了6个lysines的MED1乙化.
- 使用的MCF7 ER+ BC细胞与内源的MED1被非可乙化6KR突变体所取代.
- 采用HiCAR (可访问调节DNA上的Hi-C) 分析来评估染色体组织.
- 进行了体外试验,以分析MED1 IDRs的液态相分离 (LLPS) 特性.
主要成果:
- 表达非乙化MED1 (6KR细胞) 的细胞表现出增强的细胞生长和MED1依赖基因的高表达.
- 在6KR细胞中观察到重组的PIC组合,MED1和Pol II增加,MED17占用率下降.
- HiCAR分析显示,在6KR细胞中展开的亚TAD染色体.
- 实验室试验表明,乙化与非乙化MED1 IDR具有不同的LLPS属性,其中Pol II CTD七位数被隔离在非乙化凝缩物中.
结论:
- 它的IDR的MED1乙化协调PIC机械重组和区域色素组织.
- MED1的相位行为充当了整合基因表达的线性和空间色素功能的机械枢纽.
- 这些发现为涉及MED1/Mediator介导转录控制的疾病提供了潜在的治疗策略.
相关概念视频
Chromatin Modification in iPS Cells
1.6K
Chromatin modification alters gene expression; therefore, scientists can add histone-modifying enzymes, histone variants, and chromatin remodeling complexes to somatic cells to aid reprogramming into pluripotent stem (iPS) cells.
Compact chromatin makes reprogramming difficult. Enzymes, such as histone demethylases and acetyltransferases, are often added during reprogramming to loosen the chromatin, making the DNA more accessible to transcription factors. Molecules that inhibit histone...
Compact chromatin makes reprogramming difficult. Enzymes, such as histone demethylases and acetyltransferases, are often added during reprogramming to loosen the chromatin, making the DNA more accessible to transcription factors. Molecules that inhibit histone...
1.6K
RNA Polymerase II Accessory Proteins
9.2K
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
9.2K
Histone Modification
13.3K
The histone proteins have a flexible N-terminal tail extending out from the nucleosome. These histone tails are often subjected to post-translational modifications such as acetylation, methylation, phosphorylation, and ubiquitination. Particular combinations of these modifications form “histone codes” that influence the chromatin folding and tissue-specific gene expression.
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone...
Acetylation
The enzyme histone acetyltransferase adds acetyl group to the histones. Another enzyme, histone...
13.3K
Spreading of Chromatin Modifications
8.3K
The histone proteins in the nucleosomes are post-translationally modified (PTM) to increase or decrease access to DNA. The commonly observed PTMs are methylation, acetylation, phosphorylation, and ubiquitination of lysine amino acids in the histone H3 tail region. These histone modifications have specific meaning for the cell. Hence, they are called "histone code". The protein complex involved in histone modification is termed as "reader-writer" complex.
Writers
The writer...
Writers
The writer...
8.3K
Co-activators and Co-repressors
7.3K
Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
7.3K
Chromatin Structure Regulates pre-mRNA Processing
7.0K
In eukaryotic cells, nascent mRNA transcripts need to undergo many post-transcriptional modifications to reach the cell cytoplasm and translate into functional proteins. For a long time, transcription and pre-mRNA processing were considered two independent events that occur sequentially in the cell. However, it has now been well established that transcription and pre-mRNA processing are two simultaneous processes that are precisely regulated inside the cell.
The chromatin structure, especially...
The chromatin structure, especially...
7.0K


