The structural organization of chromosomes is essential for their correct 
function and dynamics during the cell cycle. The assembly of DNA into chromatin 
provides the substrate for topoisomerases and condensins, which introduce the 
different levels of superhelical torsion required for DNA metabolism. In 
particular, Top2 and condensin are directly involved in both the resolution of 
precatenanes that form during replication and the formation of the 
intramolecular loop that detects tension at the centromeric chromatin during 
chromosome biorientation. Here we show that histone depletion activates the 
spindle assembly checkpoint (SAC) and impairs sister chromatid decatenation, 
leading to chromosome mis-segregation and lethality in the absence of the SAC. 
We demonstrate that histone depletion impairs chromosome biorientation and 
activates the Aurora-dependent pathway, which detects tension problems at the 
kinetochore. Interestingly, SAC activation is suppressed by the absence of Top2 
and Smc2, an essential component of condensin. Indeed, smc2-8 suppresses 
catenanes accumulation, mitotic arrest and growth defects induced by histone 
depletion at semi-permissive temperature. Remarkably, SAC activation by histone 
depletion is associated with condensin-mediated alterations of the centromeric 
chromatin. Therefore, our results reveal the importance of a precise interplay 
between histone supply and condensin/Top2 for pericentric chromatin structure, 
precatenanes resolution and centromere biorientation.