Figure 1. Experimental design.

(A) Schematic of Myh11-CreER^T2, ROSA26 STOP-flox eYFP^+/+ (SMC-YFP) mice. Upon tamoxifen injection, any cell transcribing Myh11 underwent excision of a floxed STOP codon in front of an eYFP transgene driven by the ROSA26 locus, allowing for permanent eYFP labeling of SMCs and their progeny. (B–D) SMC-YFP, Apoe^–/– littermates at 9 weeks of age were subjected to 0 (nonirradiated, non-BMT controls) or 1,200 cGy of ionizing radiation and then administered >1 × 10⁶ bone marrow cells (BMT). (B) Following 6 weeks of recovery to allow bone marrow engraftment, the mice were placed on a Western diet for 18 weeks to induce atherosclerosis formation. (C) Directly after radiation, mice were given a single BrdU pulse (10 mg/ml) and harvested at 1, 4, or 7 days after irradiation or 5 days after BrdU pulse for nonirradiated, non-BMT controls. (D) Following 6 weeks of recovery to allow bone marrow engraftment, mice underwent carotid ligation or femoral wire injury for 21 days. Bone marrow donor lines are indicated for each experiment. (E) Delineation of cut sites for vessels excised from the aortic outflow tract