Molecular Mechanism Of The Porcine G0S2and The Genetic Effect Of H-FABP And ACSL4SNPs Locus On Fat Traits

Fat trait is an important economic character of pigs. The synthesis and catabolism of pig fat directly affect the pork quality. The adipose triglyceride lipase (ATGL) is the rate-limiting enzyme of triglyceride hydrolysis. The GO/G1switch gene2(GOS2) as an inhibitor for the ATGL participates in the regulation of triglyceride catabolism. Althoughthe researches on GOS2molecules of the mouse and human primarily revealed the physiological functions of the GOS2in lipid metabolism, the molecular mechanism in vivo, especially pigs, needs further research. As two important genes affecting the animal’s fat metabolism, heart-type fatty acid binding protein gene (H-FABP) and Long-chain acyl-CoA synthetase gene (ACSL4) are considered asthe candidate genes which influence the of intramuscular fat content. The study two genetic mutation loci for intramuscular fat content and back fat thickness of genetic effect of pigs can provide the tag information for molecular breeding pig. The molecular mechanism of GOS2gene was researched by using molecular biology techniques at the levels of molecules, individuals and groups. This experiment studies the molecular mechanism of GOS2gene by using molecular biology experimental technique. Meanwhile, the genetic diversity of the porcine H-FABP and ACSL4gene for the Intramuscular fat content and back fat thickness were researched.. The results are as follows:1. We obtained the complete length of porcine GOS2gene is953bp, which was composed of two exons and one intron, and encoding103amino acid residues. At the amino acid level, the homology of pig with human, mouse and cattle are66%,62%and68%respectively.2. The mRNA transcription levels of the GOS2gene was detected by quantitative real time PCR(qPCR) of17organizations of the180-day-old pigs (heart, liver, spleen, lung, kidney, stomach, intestine, eye muscle, the psoas muscle, ovary, testicle, outer layer of subcutaneous fat, inner layer of subcutaneous fat, greater omentum, lesser omentum, abdominal fat and suet fat), and analyzed the gender affects on the gene transcription levels. The results showed that GOS2gene mRNA in testing organizations all have different degree of expression, but mainly expressed in the liver tissue, followed by adipose tissue, while the ATGL gene was highly transcribedin adipose tissue. Gender impacted GOS2gene transcription in the organization. The GOS2transcription levels in male pigs were significantly higher than that of spleen, intestines, stomach and liver tissue of female pig (P<0.05). The GOS2gene transcription levels in female were significantly higher than that ofsuet and subcutaneous tissueof the male pig (P<0.05).3. The five groups (Yanan, jinhua, Yorkshire, landrace and Duroc) over266individual GOS2gene directly sequencing by direct sequencing method. Screened over porcine GOS2gene19variable sites, including four sites in the coding region,307A>T site caused by threonine�'Serine;394C>G site caused by Leucine�'valine;565G>A sites caused by Valine�'Methionine;566T>C loci cause Valine�'Alanine;565G>A sites and566T>C loci common caused by Valine�'Threonine.4. The GOS2gene polymorphism loci and intramuscular fat content and back fat thickness awere analyzed in chain In Yanan pig populations. The results showed that565G>A and742T>A sites and backfat thickness weresignificantly correlated (P<0.05). The distributions of these two genotypes of polymorphic locit were significant differences (P<0.01) in the five varieties.5. The three polymorphic sites (Hinfl, MspⅠ and HaeⅢ) of H-FABP gene in the four outside groups of pigs (Duroc, Yorkshire, Landrace and DLY) showed polymorphism. Yanan and Jinhua pig only showed polymorphic in Hinfl sites, MspⅠ and HaeⅢ of sites was monomorphic. Analysis of genetic effects found that the Hinfl sites significant impacedt the content of the IMF in Yanan and DLY pigs, which pigs carrying the HH genotype have a higher IMF content.6. ACSL4gene RsaI polymorphic loci appeared in the four outside groups of pigs (Duroc, Yorkshire, Landrace and DLY), but Yanan and Jinhua pigs showed monomorphic. Genotype distributing between species and gender was remarkablely difference. Analysis of Genetic Effects found thatReaI sites weresignificantly affect the IMF content in the DLY groups, and the IMF content of the individual with genotype GG in female pigs or haplotype G in male pigs was higher than that with genotype AA.