Spindle architecture in mono astral mammalian spindles

Faithful chromosome segregation relies on a precisely balanced network of forces within the mitotic spindle. In this project, we perturb these forces by inhibiting the outward sliding activity of the motor protein kinesin‑5 (Eg5). Loss of Eg5 function causes spindle collapse, resulting in a mono‑astral spindle in which the two poles fail to separate. By applying a small‑molecule inhibitor to block kinesin‑5 activity, we generate this controlled, tension‑reduced state, providing a powerful experimental system to analyze the organization of kinetochore microtubules (KMTs) and non‑KMTs in the absence of bipolarity.

Using quantitative analysis of serial‑section electron tomograms, we aim to uncover:

What is the three‑dimensional (3D) organization of KMTs in Eg5‑inhibited spindles?
How do non‑KMTs reorganize in mono‑astral spindles?
How is the centrosomal architecture altered in collapsed spindles?

This work enables us to dissect the mechanics of spindle assembly by examining how the system reorganizes when a major force‑generating pathway is removed. Understanding these architectural principles will shed light on the fundamental mechanisms of KMT organization that ensure accurate chromosome segregation in mitotic cells.