Phylogenetic and expression analysis of the angiopoietin-like gene family and their role in lipid metabolism in pigs

Abstract

Objective: The objective of this study was to investigate the phylogenetic and expression analysis of the angiopoietin-like (<i>ANGPTL</i>) gene family and their role in lipid metabolism in pigs.Methods: In this study, the amino acid sequence analysis, phylogenetic analysis, and chromosome adjacent gene analysis were performed to identify the <i>ANGPTL</i> gene family in pigs. According to the body weight data from 60 Jinhua pigs, different tissues of 6 pigs with average body weight were used to determine the expression profile of <i>ANGPTL1-8</i>. The ileum, subcutaneous fat, and liver of 8 pigs with distinct fatness were selected to analyze the gene expression of <i>ANGPTL3, ANGPTL4</i>, and <i>ANGPTL8</i>.Results: The sequence length of <i>ANGPTLs</i> in pigs was between 1,186 and 1,991 bp, and the pig <i>ANGPTL</i> family members shared common features with human homologous genes, including the high similarity of the amino acid sequence and chromosome flanking genes. Amino acid sequence analysis showed that <i>ANGPTL1-7</i> had a highly conserved domain except for <i>ANGPTL8</i>. Phylogenetic analysis showed that each ANGPTL homologous gene shared a common origin. Quantitative reverse-transcription polymerase chain reaction analysis showed that <i>ANGPTL</i> family members had different expression patterns in different tissues. <i>ANGPTL3</i> and <i>ANGPTL8</i> were mainly expressed in the liver, while <i>ANGPTL4</i> was expressed in many other tissues, such as the intestine and subcutaneous fat. The expression levels of <i>ANGPTL3</i> in the liver and <i>ANGPTL4</i> in the liver, intestine and subcutaneous fat of Jinhua pigs with low propensity for adipogenesis were significantly higher than those of high propensity for adipogenesis.Conclusion: These results increase our knowledge about the biological role of the ANGPTL family in this important economic species, it will also help to better understand the role of ANGPTL3, ANGPTL4, and ANGPTL8 in lipid metabolism of pigs, and provide innovative ideas for developing strategies to improve meat quality of pigs.