positive regulation of sister chromatid cohesion

Definition

Target type: biologicalprocess

Any process that activates or increases the frequency, rate or extent of sister chromatid cohesion. [GOC:go_curators]

Positive regulation of sister chromatid cohesion is a crucial biological process that ensures the accurate segregation of duplicated chromosomes during cell division. This process involves the establishment and maintenance of a close association between sister chromatids, which are identical copies of a chromosome produced during DNA replication. This association is mediated by a protein complex called cohesin.

Cohesin is loaded onto DNA during S phase, the phase of the cell cycle where DNA replication occurs. The cohesin complex is composed of four core subunits: SMC1, SMC3, SCC1, and STAG1/2. SMC1 and SMC3 are structural maintenance of chromosomes (SMC) proteins that form a ring-like structure that encircles the DNA. SCC1, also known as RAD21, is a kleisin protein that bridges the two SMC subunits. STAG1 or STAG2 is a protein that interacts with SCC1 and provides specificity to the cohesin complex.

Once loaded onto DNA, cohesin establishes a stable association between sister chromatids. This association is maintained throughout the remainder of the cell cycle until the onset of mitosis. During mitosis, cohesin is removed from chromosomes in a regulated manner, allowing the sister chromatids to separate and segregate to opposite poles of the dividing cell.

The process of positive regulation of sister chromatid cohesion involves several key steps.

* **Establishment of cohesion:** This step involves the loading of cohesin onto DNA during S phase. The loading process is regulated by several factors, including the cell cycle checkpoint proteins and the DNA replication machinery.
* **Maintenance of cohesion:** Once loaded onto DNA, cohesin needs to maintain its association with sister chromatids throughout the cell cycle. This maintenance requires the activity of various enzymes, including the cohesin acetylase ESCO2 and the cohesin decatenase TOP2A.
* **Regulation of cohesion during mitosis:** During mitosis, the cohesion between sister chromatids needs to be carefully regulated to ensure that the sister chromatids remain associated until the appropriate time for their separation. This regulation is mediated by a complex network of signaling pathways, including the spindle assembly checkpoint, which ensures that all chromosomes are correctly attached to the spindle microtubules before the sister chromatids are allowed to separate.

The proper regulation of sister chromatid cohesion is essential for maintaining genome stability. Errors in this process can lead to aneuploidy, a condition where cells have an abnormal number of chromosomes, which is associated with various diseases, including cancer. Furthermore, disruption of cohesin function can lead to premature chromosome segregation, leading to genomic instability and developmental defects.'
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Proteins (1)

Compounds (3)