Figure 1

CSE2 (YY1 binding sites) functions as a transcriptional activator. The top panel shows the genomic layout of the mouse Peg3-DMR along with the two evolutionarily conserved sequence elements, the CSE1 (open square) and the YY1 binding sites (open oval). The thick vertical lines indicate the positions of the 1^st and 2^nd exons of Peg3. Each of the constructs differs from the others by the orientation and number of YY1 binding sites: the intact versus mutated YY1 binding sites (-Y or -mY), the orientation of the YY1 binding sites (-F or -R), and the numbers of mutated YY1 binding sites (-1 mY to -6 mY) (A&B). Black ovals represent mutated YY1 binding sites. The promoter activity of each construct was analyzed more than three times, and the averaged value was derived along with S.D. (Standard Deviation). The averaged value for each construct was further compared with that of the reference constructs. The two sets of promoter assays were conducted at two different times with two different reference constructs: Construct 1+C (A) and Construct 1+C+YF (B). In order to compare the results from these two different series, the averaged value for the reference construct (1+C+YF) of the second set was adjusted to 1.7 since the same construct derived the 1.7 fold relative to the reference construct (1+C) of the first set. These promoter assays were performed using three different cell lines, Neuro2A, NIH3T3, and HeLa. Only the result set from the Neuro2A cell line is shown in the graph since the other two result sets derived from NIH3T3 and HeLa cells showed almost identical patterns [see Additional file 1].