Identification of KLF10 expression in PACs and responsiveness to TGF-β1. (A-B) BM-derived progenitors grown in either hematopoietic IMDM medium or EGM-2 were harvested, and expression of Klf10 was examined by quantitative PCR (A) or Western blot analysis (B). *P < .01. β-actin was used as an internal loading control. (C-D) BM-derived progenitors grown in EGM-2 medium in the presence or absence of TGF-β1. Klf10 mRNA expression was examined in GMP-derived PACs by quantitative PCR (C). *P < .01 versus no TGF-β1. (D) VEGFR2 expression was examined by flow cytometry for the indicated WT or KLF10^−/− PACs (n = 3 per group); *P < .01 versus WT. (E-F) BM-derived progenitors were transduced with retrovirus GFP-RV-EV (empty vector; ctrl) or GFP-RV-KLF10. The percentage of GFP⁺ cells that also expressed VEGFR2 in WT CMP-, GMP-, and HSC-derived PACs (E) or TGF-β1⁺/⁺ and TGF-β1^+/− CMP-derived PACs (F) was assessed by FACS. *P < .01 versus empty EV; **P < .05 versus EV TGF-β1⁺/⁺. (G) ChIP analysis of KLF10 binding to the VEGFR2 promoter in GMP-derived PACs. IgG was used as a nonspecific control. Assays were performed in triplicate by real-time quantitative PCR with the use of primers at −294 bp and −30 bp of the VEGFR2 promoter. Values are presented as relative to DNA input. *P < .01 versus without TGF-β1 treatment.