Fig. 8. CRM1 is required for the retention of snRNPs in CBs. The loss of PA-GFP-Sm from CBs was measured in HeLa cells before and after treatment for 2 hours with LMB. (A) Average intensity of CBs over time, corrected for bleaching of the sample and expressed as a percentage of the pre-bleach intensity of each CB. The loss of PA-GFP-SmB from CBs is more rapid in cells treated with LMB. (B) Mean half-lives of loss of PA-GFP-SmB from CBs under control and LMB-treated conditions.