Fig. 4

Both C/EBPα-p42 and C/EBPα-p30 directly bind to DDIT3 promoter but regulate its transcription in an antagonistic manner. A ChIP-seq of C/EBPα revealed a C/EBPα binding site localized in the promoter region of DDIT3 (Chr12:57520654–57521026). B C/EBPα-p42 inhibited the transcription of DDIT3, while C/EBPα-p30 exerted an activation effect. C After adding tunicamycin (100 ng/ml, 24 h) to induce the terminal UPR, the transcriptions of luciferase were further increased on the basis of the original lower level in the HEK293T cells expressing C/EBPα-p42 and C/EBPα-p30, and the cells in the control group. D When the ChIP-peak region (Chr12:57520654–57521026) was deleted, the activation effect of C/EBPα-p30 on DDIT3 transcription was disrupted, whereas the suppression effect of C/EBPα-p42 was sustained. E Schematic diagram of two potential C/EBPα binding motifs determined by using the JASPAR database and the potential C/EBPα binding regions detected by ChIP-qPCR. F–H ChIP-qPCR revealed that C/EBPα-p30 showed stronger affinity than C/EBPα-p42 in (F) and near (G) the ChIP-peak region, while sharing the same affinity with C/EBPα-p42 at a position far from the peak (H). Data represent Mean ± SD (n = 3); *P < 0.05; **P < 0.01, ***P < 0.001, ****P < 0.0001