The release of duplicated mitotic spindle pole bodies (SPBs) that begins with the nucleation of microtubules from each SPB within the nucleus, leading to V-shaped spindle microtubules. Interpolar microtubules that elongate from each pole are interconnected, forming overlapping microtubules. Capturing and antiparallel sliding apart of microtubules promotes the initial separation of the SPB.
initial mitotic spindle pole body separation