Community Research and Development Information Service - CORDIS

New functions of organelles involved in cytokinesis

Cytokinesis is the process of cell division in which the cytoplasm of a single animal cell is divided between two daughter cells. Organelles involved in cytokinesis may have additional functions in cell biology.
New functions of organelles involved in cytokinesis
Many of the additional functions of cytokinesis and the underlying mechanisms are not well understood. The EU-funded CYTODEV (Functions of the midbody ring in embryogenesis and tumorigenesis) project focused on the function of the midbody ring (MR) that forms at the site of abscission during cytokinesis.

MR is a protein-dense organelle that forms only once during cell division. It can be inherited by only one of the two daughter cells, creating an asymmetry in the process of cytokinesis. Previous research implicated MR in sequestering stem-cell markers and mediating differentiation and pluripotency in vitro. CYTODEV scientists undertook a multidisciplinary approach using microscopy, computational image analysis, and developmental genetics to investigate how asymmetric MR inheritance may affect cell functions.

The MR contains bundles of microtubules derived from the mitotic spindle, which compacts during the final stages of cell division. It has a typical diameter of one micrometre and a length of three to five micrometres. It also contains various proteins involved in cytokinesis, cell division, and chromosome segregation.

In the course of the project, researchers tracked MRs using 3D cell and object racking during wild type development and found that their inheritance follows a gradient of cortical contractility from anterior to posterior. They also analysed the mechanism of stereotyped MR inheritance in the early embryo. Analyses showed that rotational cortical flow positioned the MRs of the previous division asymmetrically at the future ventral side of the embryo.

In the neighbouring embryo, astral microtubules contact a transient actin coat that forms asymmetrically on the MR interface. Ablation of the MRs or perturbation of rotational cortical flow demonstrated that microtubule-MR contacts are crucial for spindle rotation and axis formation. In conclusion, the new data suggested a mechanism for dorsoventral patterning that relies on coupling of anteroposterior polarity, rotational cortical flow, MR positioning, and spindle orientation.

The CYTODEV study demonstrated that MRs are not passive structures and participate in polarisation events during development. The study provided new mechanistic insights into the role of this animal cell organelle with implications for human development and disease.

Related information


Cytokinesis, CYTODEV, object tracking, midbody ring, polarisation
Record Number: 188575 / Last updated on: 2016-09-19
Domain: Biology, Medicine