Fig. 1

Validation of the pDR reporter vector and bidirectional transcription from human bidirectional promoters. a Schematic for orientation of the pDR vector mimicking the organization of bidirectional gene pairs and CMV cloned in sense orientation to either reporter. Images below depict immunofluorescence for pDR vector validation with CMV. Scale bar = 400 μm. b Flow cytometry analysis of HEK293T cells transfected by pDR vector and CMV containing pDR vector for validation of promoter activity. Flow cytometry supports microscopy analysis, revealing that there is no transcription from pDR vector alone. CMV promoter clones exhibit transcription of only one of the two reporters and simultaneous reporter transcription of both is virtually undetectable. c Schematic shows human GAPDH promoter cloned in pDR in sense orientation to eGFP. Fluorescence imaging for HEK293T cells transfected with this vector is shown below the schematic. d The human GAPDH promoter cloned in pDR in sense orientation to mCherry. Images below show fluorescence imaging for HEK293T cells transfected with this vector. e Eight intergenic regions from known bidirectional gene pairs cloned in an orientation sense to the eGFP ORF show transcription in either orientation as assayed by eGFP and mCherry fluorescence. The merged images indicate both reporters are transcribed in the transfected cells. Antisense orientation data is presented in Additional file 1: Figure S1. f FACS analysis of HEK293 cells transfected with each of the 8 bidirectional promoters. Both reporters are co-expressed in each of bidirectional genes tested