A comparison of B cells’ expression at 48 and 72 h after anti-DEC-OVA treatment ruled out downregulation of Aicda as the mechanism for this pause in SHM. We also confirmed downregulation of Aicda as the mechanism for this pause in SHM. The localization-based readout for CDK2 activity is determined as theTomato-to-nuclear (C/N) ratio of DHB–tdTomato.