Expression Patterns of SREBF1 and SREBF2 in Liver and Adipose Tissues of Two Fat-Tailed Sheep Breeds

Abstract Background The fat-tailed sheep is raised largely in China and other countries due to its high adaptability to nutritionally challenging environments and disease resistance as well as fat deposition in tails. So the purpose of the study is to explore the expression pattern and regulation mechanism of sterol regulatory element binding proteins (SREBPs) in liver and adipose tissues of fat-tailed sheep bases on its role in fat metabolism and deposition with sheep grown and development. Methods Two representative Chinese fat-tailed sheep breeds i.e. Guangling Large Tailed (GLT) and Small Tailed Han (STH) were employed to evaluate the ontogenetic expressions of SREBF1 and SREBF2 from seven different adipose tissues and liver at 4, 6, 8, 10 and 12 month by real-time PCR. Five serum indicators were detected, and the function speculation of SREBP1 and SREBP2 were evaluated by bioinformatics approaches. Results Serum indicators, especially total cholesterol TC and non-esterified fatty acid (NEFA) showed obvious differences and dynamical changes with the different development ages, gender factors only had a significant effect on serum NEFA concentrations. Both SREBF1 and SREBF2 mRNA expression in sheep were significantly affected by breed, tissue, age factors, and show a significant positive correlation (r = 0.286). Merely the expression of SREBF1 gene in STH is significantly higher than that in GLT, but SREBF2 gene expression is opposite. The expressions of SREBF1/2 in liver are extremely higher than that in seven adipose tissues, the interaction of two factors between breed and month age, breed and tissue, and tissue and gender also significantly affects its expression. Subcellular locations and function prediction imply that SREBP1/2 expressions are closely related with metabolism processes in cells. Conclusions The mRNA expression profiling of SREBF1 and SREBF2 showing a breed-specific, gender-specific, and temporal and spatial expressions differences, which imply that SREBF1/2 play a crucial role in lipid metabolism regulation during growth and development of two fat-tailed sheep. This study provides a phenotypic basis for further revealing the genetic mechanism in lipid metabolism and fat deposition that causes differences in ovine tail types, which also provides a novel insight for improving quality of meat.