一个线粒体的书签协调了Drosophila胚胎中的转录和复制
Chun-Yi Cho1, Patrick H O'Farrell1
1Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, United States.
Nucleic acids research
|December 31, 2025
概括
为了防止碰撞,Cdc7分散Brd4,延迟转录直到复制开始后. 这种时间顺序确保复制分叉在胚胎早期发育期间不会阻碍基因转录.
科学领域:
- 分子生物学分子生物学
- 发展生物学 发展生物学
- 遗传学 是一个遗传学.
背景情况:
- DNA复制叉和RNA转录之间的碰撞对基因组稳定性构成重大威胁.
- 协调复制和转录至关重要,特别是在像早期多索菲拉胚胎这样的快速细胞周期期间.
- Brd4蛋白以前已被确定为转录必不可少的蛋白质,并形成活跃基因的枢纽.
研究的目的:
- 调查Brd4和Cdc7在早期Drosophila胚胎发生过程中协调复制和转录中的作用.
- 了解如何实现复制和转录的时间顺序,以防止碰撞.
主要方法:
- 使用Drosophila melanogaster作为一个模型生物.
- 研究了Brd4在线粒染色体上的持久性.
- 通过Cdc7.7检查了Brd4依赖焦点的形成.
- 评估Cdc7抑制对复制时间和转录的影响.
主要成果:
- Brd4 存在于线粒染色体上,作为转录激活的书签.
- Cdc7在无相进入时形成了Brd4依赖的焦点,促进了早期的复制.
- Cdc7活动分散了Brd4,推迟了转基因后转录,直到新的Brd4枢纽组装起来.
- 抑制Cdc7延迟了复制,并导致过早转录与延长缺陷.
结论:
- Cdc7触发了Brd4中的功能开关,在复制和转录启动之间强制执行时间顺序.
- 这种时间调节最大限度地减少了复制叉和延长的转录之间的碰撞.
- 这些发现表明了转录活动和早期复制时间之间的相关性机制.
相关概念视频
02:04Polytene Chromosomes
10.8K
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...
10.8K
02:50Spindle Assembly
4.2K
Spindle assembly occurs through three, often coexisting, pathways – the centrosome-mediated pathway, the chromatin-mediated pathway, and the microtubule-mediated pathway – collectively contributing to form a robust spindle apparatus.
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a...
In most cells, centrosomes are the primary microtubule nucleation centers. In the centrosome-mediated pathway, the G2-prophase transition triggers centrosome maturation and increased microtubule nucleation. Progressive nucleation results in a...
4.2K
02:57Meiosis vs. Mitosis
69.1K
Cell division is necessary for growth and reproduction in organisms. Mitosis aids cell growth and development by dividing somatic cells. In contrast, meiosis causes the division of germ cells and plays an essential role in sexual reproduction. Due to their unique functional requirements, mitosis and meiosis differ from each other in multiple aspects.
Before the start of mitosis and meiosis I, the cell synthesizes DNA, resulting in two homologous copies of each chromosome. DNA synthesis is...
Before the start of mitosis and meiosis I, the cell synthesizes DNA, resulting in two homologous copies of each chromosome. DNA synthesis is...
69.1K
02:38Heterochromatin
17.7K
The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions that take up more dye are called heterochromatin. Heterochromatin is further classified into two forms – constitutive heterochromatin and facultative heterochromatin.
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at...
Constitutive heterochromatin: It is a highly compact region of chromatin that is mostly concentrated in the centromere and telomere. Unlike euchromatin, the amino acid at...
17.7K
02:19The Spindle Assembly Checkpoint
3.6K
The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
3.6K
02:27The Mitotic Spindle
7.7K
The mitotic spindle—or spindle apparatus—is a eukaryotic, cytoskeletal structure made up of long protein fibers called microtubules. Formed during cell division, the spindle separates sister chromatids and moves them to opposite ends of a parental cell, where the now individual chromosomes are distributed to two daughter cell nuclei.
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures...
The bipolar configuration of the mitotic spindle facilitates chromosomal segregation, preparing the cell for division. One mechanism that ensures...
7.7K