FOXF1 promoter-putative enhancer chromatin looping

To determine if there is a physical interaction between the FOXF1 promoter and putative enhancer sequences ~250kb upstream of the promoter chromosome conformation capture-on-chip (4C) analysis was performed. An unanticipated and tremendous amount of the non-coding sequences of the human genome are transcribed. Long non-coding RNAs (lncRNAs) are non-protein coding transcripts longer than 200 nucleotides and their functions remain enigmatic. We demonstrate that deletions of lncRNA genes cause a lethal lung developmental disorder, Alveolar Capillary Dysplasia with Misalignment of Pulmonary Veins (ACD/MPV), with parent of origin effects. We identify non-coding overlapping deletions 250 kb upstream to FOXF1 in nine patients with ACD/MPV that arose de novo specifically on the maternally inherited chromosome and delete a fetal lung-specific EST, part of an lncRNA. These deletions define distant cis-regulatory region that harbors a differentially methylated CpG island, binds GLI2 depending on the methylation status of this CpG island, and physically interacts with and up-regulates the FOXF1 promoter, consistent with the absence of the fetal lung-transcribed lncRNA perturbing FOXF1 regulation. LncRNA-mediated chromatin interactions may be responsible for position effect phenomenon and potentially cause many disorders of human development. 4C analysis using 16q24.1 specific 3x720K arrays demonstrated physical interaction between the FOXF1 promoter and distant putative regulatory sequences, about 250 kb upstream in human pulomonary microvascular endothelial cells; 2 biological replicates performed; this chromatin looping was not detected in lymphoblasts that do not express FOXF1 and hence serve as a negative control.