This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: At the scale of individual cells, the human body is constantly in motion. Every second, millions of cells divide, particularly in tissues such as the bone marrow, intestine and skin; neurons and heart muscle cells divide far less frequently.
All of this depends on the molecular machinery responsible for copying the billions of chemical units that make up DNA inside the nucleus. Despite being essential for life, cell division continues to reveal unexpected mechanisms. An international team from the Institute of Molecular Cancer Research (IMCR) at the University of Zurich and the Spanish National Cancer Research Centre (CNIO) reports the discovery of a fundamental process that cells use during division to safeguard their genetic information in Nature this week.
The researchers found that cohesin, a key cellular protein, acts as a molecular anchor that helps reorganize newly replicated DNA and prevents potentially harmful errors when DNA replication encounters problems. Cohesin is one of the most important proteins involved in cell division. Its function has been preserved throughout evolution, with cohesin proteins in organisms as distant as fungi and humans sharing remarkable similarities.
Until now, cohesin was mainly known for two essential roles. First, it holds together the two copies of each chromosome generated before cell division, ensuring their correct distribution into daughter cells. Second, it helps newly replicated DNA adopt the correct three-dimensional organization inside the nucleus.
Both functions are crucial. DNA molecules are several meters long when fully extended, yet they must fit inside a microscopic nucleus. This requires precise folding because the three-dimensional organization of DNA influences how different regions of the genome communicate with one another.
"DNA folding by cohesin is not simply a way to make the molecule fit inside the nucleus. It brings together regions of the genome that may be far apart along the DNA sequence, allowing distant genes to coordinate their activity," explains Ana Losada, head of the Chromosome Dynamics Group at CNIO. The idea that genome organization influences gene activity has emerged relatively recently, and the role of cohesin in this process is an active area of research.
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