Fig. 3.

Pax7 implements melanotrope features onto a shared pro-opiomelanocortin (POMC) cell identity. a t-Distributed stochastic neighbor embedding (t-SNE) map of adult pituitary cells colored for expression of the POMC lineage regulator Tpit (Tbx19). Enlarged panels showing two clusters of POMC cells with high and low POMC levels, melanotropes expressing Pax7, and corticotropes expressing GR. b Volcano plot showing differential transcription factor gene expression (p value versus log 2 fold change (FC)) between the high versus low POMC-expressing cells. GR and Pax7 are highlighted. c Experimental scheme to assess Pax7 dependence of melanotrope phenotypic features. Transgenic mice expressing POMC-EGFP (enhanced green fluorescent protein) were crossed into Pax7−/− mice and compared to wild-type (WT). The two pituitary lobes were dissected for each genotype and analyzed by fluorescence-activated cell sorting (FACS). d Representative FACS profiles showing cell populations with different POMC-EGFP transgene levels in intermediate (IL) and anterior lobes (AL) of WT (n = 5) and Pax7 KO (knockout) (n = 3) pituitaries. Blue and red shading labels low and high EGFP levels, respectively. e Bar graph showing ratios of EGFP signals in WT IL, Pax7 KO AL, Pax7 KO IL compared to WT AL. The analyses included five WT and three Pax7 KO replicates. P values were computed using unpaired two-sided t test