Contrary to what textbooks have claimed for over a century, cell division does not always follow the same pattern. Researchers have just demonstrated that cells can divide asymmetrically, overturning the foundations of taught biology.
This discovery, published in
Science, reveals that the division process does not systematically involve a spherical shape. Cells adopt much more varied behaviors, influenced by their initial morphology.
Cell shape, a key factor in asymmetric division
Observations show that short, wide cells tend to round up before splitting into two identical cells. In contrast, elongated cells maintain their shape and produce daughter cells of different sizes and functions.
This asymmetry, once associated only with stem cells, appears to play an essential role in tissue and organ formation. Researchers observed this phenomenon in zebrafish endothelial cells, which are crucial for blood vessel growth.
In the laboratory, the team reproduced these asymmetric divisions by artificially modifying the shape of human cells. This approach, called "micropatterning", confirms that parental morphology determines the type of division.
Changes in cell shape before division influence how they divide. When a cell elongates, for example while moving or on a structured substrate, it adopts an isomorphic division mode. In this mode, it maintains shape and content asymmetries throughout mitosis. This directly links interphase shape to the triggering of symmetric cell division. Major implications for medicine and research
These results could shed light on cancer progression mechanisms, where asymmetric divisions might favor tumor cell dissemination. They also open avenues in regenerative medicine by enabling better control of cell differentiation.
The technique used, based on a UV laser, offers unprecedented precision for manipulating cell shapes. This breakthrough could help design targeted therapies by guiding daughter cell fate.
Researchers now plan to study other cell types to determine the extent of this phenomenon. A revision of textbooks seems inevitable.
Article author: Cédric DEPOND