Figure 7

oPOSSUM analysis of over-represented transcription factor binding sites. Up-regulated transcripts 2, 4, and 20 hours after irradiation were uploaded to identify over-represented transcription factor binding sites in these sets of genes. Transcription factor binding sites in red highlight transcription factors enriched in the corresponding gene set. (A) Two hours after irradiation, p53 was identified as the only putative transcription factor. (B) Four hours after IR, Klf4, SP1, Zfx, and TCFCP2L1 were identified as possible transcription factors. (C) Twenty hours after irradiation Klf4, SP1, and Zfx were identified as potential transcription factors in irradiated samples. (D) PCR validation of Klf4, SP1, Zfx, TCFCP1L2, and HLF in irradiated PBMCs 20 hours after radiation confirmed the expression of these genes at the mRNA level. (E) Immunoblotting showed the presence of the predicted transcription factor proteins (Klf4, SP1, Zfx, TCFCP1L2) in both irradiated and non-irradiated samples 20 hours after irradiation. One representative experiment of two is shown. GAPDH served as a control.