DNA topoisomerases are specialized nuclear enzymes that perform topological 
modifications on double-stranded DNA (dsDNA) and hence are essential for DNA 
metabolism such as replication, transcription, recombination, condensation and 
segregation. In a genetic screen, we identified a temperature-sensitive mutant 
allele of topoisomerase 2 that exhibits conditional synthetic lethality with a 
chk1 knockout strain. The mutant allele of topoisomerase 2 is defective in 
chromosome segregation at a non-permissive temperature and there was increase in 
chromosome segregation defects in the double mutant of top2-10 and chk1 delete 
at a non-permissive temperature. More importantly, topoisomearse 2 mutant cells 
mildly delay the mitotic progression at non-permissive temperature that is 
mediated by checkpoint protein kinase Chk1. Additionally, top2-10 mutant cells 
also activate the Chk1 at a non-permissive temperature and this activation of 
Chk1 takes place at the time of mitosis. Interestingly, top2-10 mutant cells 
retain their viability at a non-permissive temperature if the cells are not 
allowed to enter into mitosis. Taking together our results, we speculate that in 
the top2-10 mutant, the segregation of entangled chromatids during mitosis could 
result in delaying the mitotic progression through the activation of Chk1 
kinase.