Cloning and expression analysis of Nrf2 gene in longissimus dorsi of Luchuan pig and Duroc×Landrace×Yorkshire pig

【Objective】To clarify biological characteristics of NF-E2-related factor(Nrf2) gene in Luchuan pig and Duroc×Landrace×Yorkshire(DLY) pig,and to explore the expression difference of Nrf2 gene in longissimus dorsi muscle of Luchuan pig and DLY pig,so as to lay a foundation for further study on the molecular mechanism of antioxidant properties of high-quality Luchuan pig muscle.【Method】The coding DNA sequence(CDS),sequence of Nrf2 gene was cloned from the total RNA of longissimus dorsi muscle of 150-day-old Luchuan pigs and the same day old DLY pigs,and the bioinformatics analysis was carried out through online softweres ExPASy ProtScale,ExPASy ProtParam and SWISS-MODEL.The expression difference of Nrf2 gene in the longissimus dorsi muscle of 150-day-old Luchuan pigs and the DLY pigs of the same age was detected by qRT-PCR and Western-blotting.【Result】The length of the CDS of Nrf2 gene of Luchuan pig and DLY pig was 1686 bp,which was compared with the CDS sequences of Sus scrofa,DLY pig,cattle,sheep,Chimpanzee,macaque,wolf,human,domestic rat,Rattus norvegicus,ostrich,ordinary domestic chicken that published in GenBank. The similarity were,99.7%,99.5%,91.2%,90.6%,90.5%,90.1%,89.5%,86.5%,81.9%,81.7%,72.0% and70.6%,respeetively. The genetic distance between Guangxi Luchuan pig and DLY pig was the nearest,and the farthest was Canis lupus. Nrf2 protein of DLY pig and Luchuan pig was composed of 561 amino acids,and serine was the highest in the amino acid content,accounting for 12.5%,and tryptophan was the lowest,accounting for only 0.4%. In the secondary structure of Nrf2 protein,random coil accounted for 57.75%,α-helix accounted for 34.05%,extended strand accounted for5.35%,β-turn accounted for 2.85% in DLY pig Nrf2 protein. The percentage of random coil,α-helix,extended strand andβ-turn were 57.93%,33.51%,6.06% and 2.50% respectively in Luchuan pig Nrf2 protein;The relative expression of Nrf2gene in longissimus dorsi muscle of 150-day-old Luchuan pigs was significantly higher than that of DLY pigs(P<0.05);The expression of Nrf2 protein in the longissimus dorsi muscle of 150-day-old Luchuan pigs was extremely significantly higher than that of DLY pigs(P<0.01).【Conclusion】Nrf2 gene CDS seqnence of Luchuan pig and DLY pig are cloned successfully,and the expression of Nrf2 in Luchuan pig is significantly higher than that in DLY pig at the same age. It is suggested that the muscle of Luchuan pig has better antioxidant activity than that of DLY pig.