Figure 2. Generation of fibroblast-specific canonical TGF-β–deleted mice.

(A) Schematic representation of different mouse lines used, including the Postn genetic locus containing a tamoxifen-regulated MCM cDNA cassette inserted into exon 1 (E1), which was crossed with Smad2- and/or Smad3-loxP–containing gene-targeted lines, along with the Rosa26 reporter allele(R26^EGFP). The mouse chromosome associated with each allele is shown. (B) Experimental scheme whereby mice were subjected to TAC injury or sham procedure for 4 and 12 weeks. Mice were fed tamoxifen diet 48 hours before surgery and then maintained on tamoxifen until harvesting. (C) Representative histological section showing EGFP-labeled interstitial cells in hearts of Postn^MCM/+ R26^EGFP/+ mice after 4 weeks of TAC injury (n = 4). Scale bar: 10 μm. (D) Western blot analysis for Smad2, Smad3, and EGFP from 500,000 cells isolated from hearts of the 2 genotypes of mice shown. (E) Western blot for Tgfbr2 in total heart mesenchymal cells lacking myocytes, CD31, and CD45 cells and conditionally targeted for Tgfbr1/2-loxP with Postn^MCM in cardiac-activated fibroblasts after TAC stimulation.