Overexpression of goat STEAP4 promotes the differentiation of subcutaneous adipocytes

Overexpression of STEAP4 could promote the differentiation of goat subcutaneous preadipocytes. This study lays the foundation for an in-depth study of the role of STEAP4 in goat lipid deposition.

The focus of this study was the six-transmembrane epithelial antigen of the prostate 4 (STEAP4) gene, on the basis of the cloned goat STEAP4 gene sequence. Its molecular and expression characteristics were analyzed, and its influence on the differentiation of goat subcutaneous adipocytes was explored through overexpression. Method: Reverse-transcription PCR (RT-PCR) was used to clone the goat STEAP4 sequence, and online tools were used to analyze the molecular characteristic. Real-time quantitative PCR (qPCR) was used to detect the expression level of STEAP4 in goat tissues and subcutaneous adipocyte differentiation. Liposome transfection, BODIPY, Oil Red O staining, and qPCR were used to explore the effect of overexpression of STEAP4 on adipocyte differentiation.

The cloned goat STEAP4 gene sequence was 1388 bp, and the complete coding sequence (CDS) region was 1197 bp, which encoded a total of 398 amino acids. Compared with the predicted sequence (XM_005679300.3), there were three base mutations in the CDS region of goat STEAP4, A188G, T281C, and A507G. Among them, A507G changed the amino acid at position 170 from Ile to Val. Analysis of the physical and chemical properties of the protein showed that STEAP4 was a stable hydrophilic basic protein. STEAP4 gene expression level was highest in goat liver tissue ( P < 0.01 <math><mrow><mi>P</mi> <mo><</mo> <mn>0.01</mn></mrow> </math> ), followed by lung and back subcutaneous adipose tissue. STEAP4 showed different expression levels in goat subcutaneous adipocytes at different times during the induction of differentiation. The expression in the late stage of differentiation was higher than that before differentiation and lowest at 12 h ( P < 0.01 <math><mrow><mi>P</mi> <mo><</mo> <mn>0.01</mn></mrow> </math> ). Overexpression of STEAP4 promoted the accumulation of intracellular lipid droplets; C/EBP β<math><mi>β</mi></math> (CCAAT enhancer binding protein) was extremely significantly up-regulated ( P < 0.01 <math><mrow><mi>P</mi> <mo><</mo> <mn>0.01</mn></mrow> </math> ), and aP2 (fatty acid binding protein) was significantly up-regulated ( P < 0.05 <math><mrow><mi>P</mi> <mo><</mo> <mn>0.05</mn></mrow> </math> ).