(A) Top, DNA content (n/2n) of exponentially growing (OD600 = 0.6-0.8) smc2-8 yeast cells. First blot: 2D gel electrophoresis of the distribution of Lk topoisomers (Lk) of the YEp13 DNA in cells quenched at 26oC and after shifting the culture to 35oC for 60 min. Second blot: 2D gel electrophoresis of the same samples upon nicking the YEp13 DNA in order to reveal the occurrence of knots (kn). Graph: Pkn of YEp13 before and after the inactivation of condensin. 