Phenotype and latency of PCTs in v-abl transgenic mice bearing 1 or 2 functional Blimp1 alleles. (A) Surface phenotypes of cells in mesenteric tumors from 3 representative Blimp1^+/+ (nos. 134, 141, and 150) and 3 Blimp1^gfp/+/v-abl transgenic mice (nos. 81, 108, and 127). Tumors were predominantly composed of Syndecan1⁺ (and GFP⁺, when the Blimp1/GFP reporter allele was present), B220⁻ cells, the phenotype of mature plasma cells. (B) Native gel electrophoresis shows clonal Ig or paraprotein (*) in the serum of PCT-bearing mice. Alb indicates albumin; and Hb, hemoglobin. (C) Tritiated-thymidine incorporation during a 6-hour culture of cell populations sorted from a Blimp1^gfp/+ tumor. (D) Genomic Southern assay showing c-myc gene rearrangements in the vicinity of the promoter. *The 3.6-kb germline band. (E) Kaplan-Meier plot of PCT incidence, by sex and genotype (●, Blimp1^+/+; ○, Blimp1^gfp/+). See “Methods” for statistical analyses. (F) Total number of ASCs in BMs (of 1 femur) and spleens. Values are means ± SDs of 4 mice (■, Blimp1^+/+; ▩, Blimp1^gfp/+). (G) Serum Igκ levels in naive, adult male B6 (Blimp1^+/+) and Blimp1^gfp/+. Values are means (± SDs) of 4 mice (■, Blimp1^+/+; ▩, Blimp1^gfp/+).