Fig. 4.

Four potential binding sites for C/EBPα in let-7a-1 gene promoter. a Schematic representation of four examined putative C/EBP binding sites in the promoter region of let-7a-1 predicted by MatInspector software. b Detection of the functions of four putative C/EBP elements by reporter gene assay. After wild-type and mutant sequences of CEBP1/2/3/4 elements as well as C/EBPα consensus sequence (CEBPcw/cm) were synthesized and inserted into reporter gene vector, the constructs were used to investigate the function and importance of these C/EBPα binding sites for let-7a-1 gene expression using dual-luciferase reporter gene assay. All of the plasmid constructs were transiently co-transfected into H1299 cells with pcDNA3.1(+)-C/EBPα, using pcDNA3.1(+) as control