Fatty acid binding protein 1 and fatty acid synthetase overexpression have differential effects on collagen III and cross-linking in Zongdihua pig tissues

The purpose of this study was to determine whether FABP1 and FAS regulate expression of collagen and its crosslinking via lysyl oxidase in Zongdihua pigs. We wished to identify processes affecting meat quality using molecular genetics to provide a basis for breeding improvement of these animals. We measured expression levels of FABP1 and related genes using qRT-PCR in longissimus dorsi muscle and subcutaneous adipose tissues. Primary adipocytes from fat tissues were isolated and FABP1 and FAS were overexpressed from recombinant plasmids. Our sequence analysis of the cloned genes indicated that FABP1 gene encodes a hydrophobic protein of 128 amino acids and contained 12 predicted phosphorylation sites and no transmembrane region. FAS encodes 333 amino acid hydrophobic protein containing with 26 phosphorylation sites and 0 transmembrane regions. The basal levels of FABP1 and FAS in pig tissues expression were 3 -3.5-fold higher in subcutaneous fat compared with muscle (P < 0.01). Recombinant expression plasmids were successfully transfected into the cloned preadipocytes and (a) overexpression of FAS resulted in significantly increased expression of COL3A1 gene (P < 0.05) and significantly inhibited lysyl oxidase LOX expression (P < 0.01); (b) overexpression of FABP1 significantly increased COL3A1 expression (P < 0.01) and significantly inhibited LOX expression (P < 0.05) and significantly reduced lysyl oxidase activity (P < 0.01). Therefore, enhancing FABP1 expression increases collagen accumulation and this preliminarily suggests that FAS and FABP1 can serve as fat-related candidate genes providing a theoretical basis for the study of fat deposition in Zongdihua pigs.