Regulation of murine follicle-stimulating hormone ß subunit transcription by newly identified enhancers [ChIP-seq; LßT2 cells]

Activin-class ligands of the TGFß 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 FSHß 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 LßT2 cells. In contrast, three other open chromatin regions enhanced basal and activin A-stimulated Fshb promoter-reporter activity in LßT2 cells, with the two most distal showing the greatest effects. Using ChIP-seq we show that these two regions exhibit enrichment of the enhancer mark H3K27ac, and are bound by SMAD2/3 and FOXL2 in response to activin A in LßT2 cells. These data are part of a SuperSeries that includes ATAC-seq data also showing these regions to be open in response to activin A in Lß?2 cells, as well as scATAC-seq data of whole mouse pituitaries indicating that there may be as many as four activin-sensitive enhancers upstream of murine Fshb. The data of this series were generated with the help of Next Gen and Bioinformatics Core services at the Salk Institute. Overall design: LßT2 cells stably expressing FLAG-tagged FOXL2 (FLAG-mFoxL2) were generated by lentivirus transduction of a cassette that permits constitutive GFP expression and tetracycline/doxycycline (DOX)-inducible, IRES-mediated tandem expression of a fluorescent reporter. LßT2-FLAG-mFoxL2 cells were cultured in plates, and DOX-induction was initiated, followed by treatment with either vehicle or activin A. Cross-linked complexes suitable for ChIP-seq were produced and enriched for SMAD2/3-, FLAG-FOXL2- and H3K27ac-bound complexes, the DNA of which was then isolated and prepared for sequencing.