ΔFosB regulates Ca2 + release and proliferation of goat mammary epithelial cells

•We characterize the function of goat ΔFosB by cloning and bioinformatics analysis.•We obtain the different expression profiling of goat ΔFosB in various tissues.•Ca2 + could increase ΔFosB levels and repress cell viability in GMECs.•ΔFosB regulates the mRNA expression of Runx2, Smad4, S100A4, and S100A13 in GMECs.•ΔFosB mediates intracellular calcium levels and cell viability in GMECs.

ΔFosB is a member of the family of transcription factor activating proteins-1 (AP-1) and is known to play important roles in Ca2 + metabolism processes of osteoblast formation and differentiation in humans and rodents. The postpartum mammary gland is one of the significant organs for Ca2 + metabolism processes. However, very little information is available on the role of ΔFosB in goat mammary gland. In this investigation, the full-length cDNA of ΔFosB from Xinong Saanen dairy goats was cloned, which contains an open-reading frame (ORF) of 723 bp encoding 240 amino acids. The amino acid sequence is highly homologous with cattle (99.17%). Quantitative real time PCR (QRT-PCR) and western blotting assays showed that ΔFosB was expressed in goat heart, liver, lung, and breast, but little in the hypophysis and spleen. The fluorescence signals revealed that the Ca2 + was decreased in goat mammary epithelial cells (GMECs) over-expressed ΔFosB at 72 h. Consistently, intracellular Ca2 + was increased in GMECs suppressing expressed ΔFosB at 72 h. QRT-PCR assay showed that ΔFosB positively regulated the mRNA expression of runt related transcription factor 2 (Runx2), SMAD family member 4 (Smad4), S100 calcium binding protein A4 (S100A4) and S100 calcium binding protein A13 (S100A13) genes in GMECs, which had been proven to be relative to calcium metabolism in humans and rodents. Ca2 + could induce a dose-dependent increase of the ΔFosB mRNA expression and a dose-dependent decrease in cell viability when the GMECs were treated with CaCl2. Suppressing ΔFosB expression in GMECs also inhibited the cell viability. These discoveries suggest that ΔFosB plays important roles in regulating Ca2 + release and proliferation of the GMECs, which may prove useful in regulation of milk production.