Study On Cloning And Expression Of Porcine PID1 Gene And Their Relationship With Intramuscular Fat Content

With the improvement of the living standard, consumers and producers pay more attention to the problem on pork quality. Genetic basis is the key to improving the meat quality. Intramuscular fat(IMF)content is an important quality indicator of measuring pork, it has a remarkable positive effect in meat tenderness, juiciness and flavor. Currently, the regulation mechanism of porcine intramuscular fat deposition is not clear, the major gene has not yet found. Greater differences in the genetic background of Laiwu pigs, cultivating varieties of Lulai Black, the introduction of the Large White variety, were selected to clone the phosphotyrosine interaction domain containing 1 and investigate this gene expression. The aim of this thesis is to provide the theoretical basis of molecular markers in MAS breeding for improving the meat quality. The results are summarized as follows:Laiwu pig was used to clone CDS of PID1 from porcine fat and muscle tissues by RT-PCR using degenerate primers(submitted to NCBI, accession number: GU396255), the CDS of PID1 was analyed by bioinformatics. The result revealed that 654 bp CDS of porcine PID1 was obtained by sequencing, the porcine PID1 protein located in the cytoplasmic, encoded 217 amino acids with a molecular weight of 54 kDa and a pI of 5.11. Protein function prediction found that PID1 gene had a phosphotyrosine-binding(PTB) domain on the position of C terminal of protein, this domain was the same as PTB in IRS1 and SHC. The results implied that they may have the same function and play an important role in sugar and fat metabolism.The mRNA distribution profile of the porcine PID1 gene in ten tissues (heart, dorsal muscles, spleen, liver, lung, small and large intestine, brain, fat and spinal) from the Laiwu pig sample were examined by QRT-PCR. The result showed that the PID1 gene was expressed in various tissues, but PID1 mRNA abundances, on the whole, tended to be heart > brain > liver > fat > longissimus muscle> lung > spinal > large intestine > spleen, small intestine was not detected. The results implied that its extensive functions for transcription.We investigated this gene expression in various tissues(liver, backfat and muscle tissues)of different breeds(Yorkshire, Laiwu and Lulai Black) by real-time fluorescence quantitative PCR. In addition, we analyed relationship between intramuscular fat content and mRNA expression of PID1 gene. The result showed that breeds factors had significant effect on PID1 mRNA aboundance(P<0.05), on the whole, tended to be Laiwu > Lulai Black > Yorkshire. Tissues factors had significant effect on PID1 mRNA aboundance(P<0.05), on the whole, tended to be liver > fat > muscle. The intercation between breeds and tissues factors had significant effect on PID1 mRNA aboundance(P<0.05). For three different intramuscular fat deposition groups of Laiwu pig(LWH, LWI, LWL), IMF factors had significant effect on PID1 mRNA aboundance(P<0.05), on the whole, tended to be LWH>LWI>LWL. Tissues factors had significant effect on PID1 mRNA aboundance(P<0.05), on the whole, tended to be liver > fat > muscle。The intercation between IMF and tissues factors had significant effect on PID1 mRNA aboundance(P<0.05). PID1 mRNA abundance was no correlated with IMF in these three tissues of Laiwu breed, but it was positively correlated with IMF in these three tissues of these three breeds (P<0.05). The results implied that the expression of PID1 may be related to fat deposition.