A Cell-Based Assay for Mitotic Spindle Orientation.

The regulation of mitotic spindle orientation is essential to ensure proper cell division and development (Kiyomitsua and Cheeseman Nat Cell Biol 14:311-317, 2012). For identification of potential spindle orientation regulators, determination of the mitotic spindle angle is a well-known but time-consuming procedure. Here we describe a simple and time-saving phenotypic screening assay for the identification of potential spindle orientation regulators. This screen is based on the analysis of monopolar mitotic spindle structures, which form upon inhibition of the mitotic kinesin Eg5/KSP by the small-molecule inhibitor dimethylenastron (DME) or similar compounds.