Conditional targeting of the CCR2 gene. (A) Top, scheme illustrating the CCR2 gene construct and the 2 loxP sites flanking exon 3, the eGFP cassette, and the PCR fragment length before and after successful recombination. Bottom left, PCR of genomic DNA isolated from various cell types and mouse mutants. Bottom right, relative expression of CCR2 in F4/80⁺ cells FACS sorted from the peritoneal cavity in diverse mouse mutants (n = 3 mice per genotype). (B) Fidelity of reporter expression in CCR2^fl/D mice: eGFP⁺ and eGFP⁻ wound cells were sorted for analysis of CCR2 mRNA expression (n = 4 wounds on 2 mice). (C) Specificity of LysMCre-mediated CCR2 gene deletion in myeloid wound cells isolated from CCR2^wt/flLysMCre mice: eGFP⁺ cells were gated and analyzed for expression of F4/80 and CD11b at different time points after injury (n = 6-8 wounds on 2-3 mice per time point). (D) Efficiency of LysMCre-mediated CCR2 gene deletion in myeloid wound cells: the frequency of eGFP⁺ cells within the gates of F4/80⁺CD11b⁺ and Gr1⁺CD115⁻ cells isolated from wound tissues of CCR2^wt/flLysMCre mice were determined and correlated with the frequency of eGFP⁺ cells within the gates mentioned above isolated from wound tissue of CCR2^fl/D mice (n = 6-8 wounds on 2-3 mice per time point). Two independent experiments were performed and data are expressed as means ± SD. **P < .01; ***P < .001.