Molecular characteristics and tissue expression analysis of FABP1 and FABP2 genes in pig

【Objective】To clarify the effect of fatty acid binding proteins(FABPs)on fat deposition in Xiangsu hybrid pigs,so as to lay the foundation for further exploring the regulatory role of FABP1 and FABP2 genes on fatty acid metabolism in adipocytes of pigs.【Method】Total RNA was extracted from the heart,liver,spleen,lung,kidney,large intestine,small intestine,longest back muscle and adipose tissue samples of Xiangsu hybrid pigs and Kole pigs,and the sequences of FABP1 and FABP2 gene coding region(CDS)of Xiangsu hybrid pigs were cloned by PCR,and were analyzed by ProtParam,ProtScale,SOPMA,SWISS-MODEL,PSORT Ⅱ Preadict and SignalP-5.0 online software for bioinformatics analysis,and RT-qPCR was used to detect the expression of FABP1 and FABP2 genes in various tissues of Xiangsu hybrid pigs and Kole pigs.【Result】CDS sequences of FABP1 and FABP2 genes of Xiangsu hybrid pigs were 384and 399 bp,encoding 127 and 132 amino acid residues,respectively,corresponding to the relative molecular weights of 14107.23 and 15217.34 Da,which are both hydrophilic proteins;their secondary and tertiary structures were dominated by β-folding and irregular coiling,with no signal peptide shear sites,and localized in the cytoplasm. The amino acid sequences of both FABP1 and FABP2 of Xiangsu hybrid pigs showed high homology with those of human,bovine and goat,and the corresponding similarities were above 80.0%,and the similarities with other reference species,except zebrafish,were also above 74.0%,so the conserved sequences of FABP1 and FABP2 genes were presumed to be high;STRING prediction results showed that the proteins that might interact with these 2 proteins were FABP5,FABP7,peroxisome proliferator-activated receptor α(PPARα),porcine apolipoprotein A4(APOA4),APOA1 and acyl-co A oxidase1(ACOX1),etc. FABP1 and FABP2 genes were expressed in all tissues of the Xiangsu hybrid pigs and Kole pigs,and were mainly expressed in various tissues,and the relative expression of FABP1 and FABP2 genes was higher in liver,small intestine and fat,while the relative expression in the longest dorsal muscle was the lowest;in addition,the relative expression of FABP1 and FABP2 genes in liver and small intestine in Xiangsu hybrid pigs was significantly higher than that in the corresponding tissues of the Kole pigs(P<0.01).【Conclusion】FABP1 and FABP2 genes are expressed in various tissues of different pigs,with specific high expression in tissues related to triglyceride and fatty acid anabolism(liver,small intestine and adipose),which may play an important role in regulating lipid anabolism.