Magic embryology: asymmetric cell division (Introduction)

by David Turell , Tuesday, March 29, 2022, 21:45 (970 days ago) @ David Turell

A new not surprising finding:

https://phys.org/news/2022-03-cell-division-embryos-textbook-case.html

"As cell biologists, Université de Montréal professor Greg FitzHarris and his Ph.D. student Lia Paim are very interested in fertility and what happens inside the eggs and embryos of the mice they study in their lab. And sometimes, they spot something unusual … by accident.

"Their latest findings, published in PNAS, could change how one particular aspect of cell division is understood and pave the way for further research on how this might play a role in the viability of the embryo—even a human one

***

"Most of our lab's experiments are about embryo development. We focus on understanding what makes the best embryo and how this relates to the embryo's potential and thus the likelihood of having a successful pregnancy.

"The mouse embryo is also a unique setting for studying cell divisions.

"In one of our experiments, Lia spotted something unusual happening during cell division. In a real-life situation such as a developing embryo in which cells are in close contact with other surrounding cells, she noticed that during the final step of cell division, called cytokinesis, the cell is pinched in two primarily from one side only.

"And she realized that the particular way in which this was occurring had not been seen by researchers before.

"The traditional textbook view of cytokinesis is that it occurs in a symmetric manner, where a pinching of the cell happens equally from both sides to cut the mother cell in two and make two new daughter cells.

"Lia discovered that molecules called cell polarity proteins have a major effect upon cytokinesis in embryos. This is why cytokinesis becomes asymmetric, quite unlike what the textbooks show.

***

"It is well known that cytokinesis sometimes fails in embryos, and that this can threaten the viability of the embryo and thus the likelihood of having a successful pregnancy, in mice as in humans. The asymmetric cytokinesis we discovered could be part of the reason for this, but we would need to do more experiments to test this possibility."

Comment: What the reviewer does not tell us is obvious: the developing embryo has to send cells in three dimensions. An asymmetric cell divisions has the necessary directionality which the modification of standard mitosis supplies. More obvious design.