Fig. 1

hnRNPA1 and CBX5 bi-directional promoter activity in breast cancer cells. a Schematized view of the CBX5 and hnRNPA1 genes (not drawn to scale). Arrows indicate direction of transcription. Localizations of transcription factor binding motifs in the bi-directional promoter were obtained from [37, 40, 41]. The HP1α coding region is indicated by black colouring. pA indicates the localization of poly-A signals. A1UCOE represents a CpG rich region homologous in localization to the characterized insulator element A2UCOE from the hnRNPA2B1 and CBX3 bi-directional promoter. b Correlation analysis of CBX5 and hnRNPA1 expression in the NCI-60 breast cancer cell panel. The analysis presented as heat map was performed using the CellMiner database, http://discover.nci.nih.gov/cellminer/, with red symbolizing positive and blue negative correlation. c Expression analysis of CBX5 and hnRNPA1 in HMEC, MCF7, and MDA-MB-231 cells. Relative expression was calculated from RT-qPCR using GAPDH expression for normalization. CBX5 primers located to exon 4 and 5 and hnRNPA1 primers to exon 1 and 2. d Transient transfection analysis of CBX5 and hnRNPA1 bi-directional promoter activity in dual reporter minigenes in MCF7 and MDA-MB-231 cells. 48 h after transfection RT-qPCR was used to detect relative expression levels of the spliced minigene derived reporter fusion transcripts. Expression of the vector co-expressed neomycin marker was used for normalization for transfection efficiency. Fold changes in expression ratio are shown in the right section. e Genomic transposition analysis of the CBX5 and hnRNPA1 bi-directional promoter activity in dual reporter minigenes in MCF7 and MDA-MB-231 cells. Stable cell lines generated by sleeping-beauty transposition of minigenes were analyzed by RT-qPCR to determine the expression levels of the spliced minigene derived reporter fusion transcripts. Because of copy integration number differences per transposition only the ratio of expression which was copy number independent is displayed. Fold changes in expression ratio are shown. For all panels, bars represent mean values with standard deviations