Effects of the transcript variants of CREB on the porcine BCL2L2 promoter. (A) Effects of CREB motif deletion on promoter activity. The putative binding site is shown above, and the sequence deleted in the mutant-type reporter gene is indicated in italics. (B) Effects of V1 overexpression on promoter activity. (C) Effects of V2 overexpression on promoter activity. (D) Effects of V3 overexpression on promoter activity. (E) Effects of V4 overexpression on promoter activity. A Student’s t-test was used to compare the differences between the two groups. * and ** indicate that the differences were significant, at p < 0.05 and p < 0.01 levels, respectively, while ns, not significant, indicates that the differences were not significant (p > 0.05).