Prefoldin is critical for meiotic spindle function, revealing coupling between chromosome segregation and cellular remodeling

The key specializations known include the addition of that allow two sequential segregation events with no intervening round of DNA segregation. Here, in contrast, we identify the ubiquitously expressed prefoldin subunit Gim3 as a critical regulator of meiotic but not mitotic chromosome segregation.

Loss of Gim3 causes pronounced chromosome mis-segregation and reduced spore viability through reduced tubulin protein levels and compromised spindle elongation. GIM3 deletion minimally affects spindle length and chromosome segregation in mitosis, despite similar tubulin levels in both cases, highlighting a previously unrecognized difference between meiotic and mitotic spindles. Beyond chromosome segregation, gim3Δ cells exhibit defects in meiotic cellular remodeling, including increased inheritance of cytosolic aggregates into newly forming spores.