Regulation of murine follicle-stimulating hormone β subunit transcription by newly identified enhancers [ATAC-seq; LβT2 cells]

Activin-class ligands of the TGFβ family induce follicle-stimulating hormone (FSH) production by pituitary gonadotrope cells in mice via the actions of the transcription factors SMAD3, SMAD4, and FOXL2, which bind to cis-elements in the FSHβ subunit (Fshb) promoter. An enhancer region for murine Fshb transcription was identified in vitro. The region, however, did not significantly alter basal or activin-stimulated murine Fshb promoter-reporter activity in LβT2 cells. In contrast, three other open chromatin regions enhanced basal and activin A-stimulated Fshb promoter-reporter activity in LβT2 cells, with the two most distal showing the greatest effects. Using ATAC-seq we show that these two regions were open in response to activin A in LβT2 cells. This data is part of a SuperSeries that includes ChIP-seq data further showing that these regions exhibited enrichment of the enhancer mark H3K27ac, and were bound by SMAD2/3 and FOXL2 in response to activin A in LβT2 cells. The SuperSeries also includes scATAC-seq data of whole mouse pituitaries indicating that there may be as many as four activin-sensitive enhancers upstream of murine Fshb.