Tissue-specific Expression And Bioinformatics Analysis Of ELOVL2 And ELOVL5 Gene Strains In Jingyuan Chicken

The elongation of very-long chain fatty acids(ELOVLs)is a kind of initiating enzyme,which is the key rate-limiting the enzyme in the synthesis of fatty acid,the ELOVL2 and ELOVL5 genes are mainly involved in the synthesis of polyunsaturated fatty acids of special nutritional value.To investigate the polymorphism,tissue-specific expression,characteristics and advanced structures of encoding proteins of ELOVLs gene,all exons,some introns of ELOVL2 and ELOVL5 genes of Jingyuan chicken were detected by PCR-SSCP and DNA sequencing in this study.The expression of ELOVL2 and ELOVL5 genes in liver,muscle,heart,testis,ovary and abdominal fat of Jingyuan chicken were detected and analyzed by qRT-PCR and we used bioinformatics methods to predict and analyze the physicochemical properties,signal peptide,transmembrane domain,hydrophilicity/hydrophobicity,secondary structure and phosphorylation sites of CDS region of ELOVL2 and ELOVL5 genes.The results of this study are as follows:1.Genetic polymorphism of ELOVL2 and ELOVL5 genes in Jingyuan chicken.There were polymorphisms in exon 7,8 and intron 2,4 and 6 of ELOVL2 gene in Jingyuan chicken.The mutations in exon 7(E2e7)and exon 8(E2e8)of ELOVL2 gene were c.708G>A and c.888T>C,respectively,which belonged to synonymous mutations.Both mutations did not show any deviation from Hardy-Weinberg equilibrium(P>0.05).Five genotypes,four alleles and three SNPs were detected in amplified fragments of intron 2(E2I2)of ELOVL2 gene,including g.63372228+4918G>A,g.63372228+5024T>C and g.63372228+4928C>A,respectively.Three genotypes,two alleles and one mutation site were detected in amplified fragment of intron 6(E2I6)of ELOVL2 gene,which was a transversion of g.63388000+748G>C.Four genotypes,three alleles and two SNPs were detected in amplified fragment of intron 4(E2I4)of ELOVL2 gene,g.63386502+165T>C and g.63386502+211A>G,respectively.Population genetic analysis showed that SNPs of E2I2,E2I4 and E2I6 were moderate polymorphic and deviated from Hardy-Weinberg equilibrium(0.01<P<0.05).There was no mutation in the exon of ELOVL5 gene,but two genotypes and one SNP locus were detected in amplified fragment of intron 2(E5I2),which was g.88620433+1683G>A,showing a low polymorphism and did not deviate from Hardy-Weinberg equilibrium(P>0.05).2.Temporal and spatial expression of ELOVL2 and ELOVL5 genes in Jingyuan chicken.ELOVL2 and ELOVL5 genes were expressed in abdominal fat,liver,muscle,testis,heart and ovary of Jingyuan chicken.The relative expression of ELOVL2 and ELOVL5 genes in liver were the highest and significantly higher than that in other tissues(P<0.05).By analyzing and comparing the differential expressions of ELOVL2 and ELOVL5 genes in diverse tissues,it was found that the expressions of ELOVL2 and ELOVL5 genes in abdominal fat were significantly different(P<0.05).3.Bioinformatics analysis of CDS region of ELOVL2 and ELOVL5 genes in Jingyuan chicken.The ELOVL2 gene has an open reading frame(894 bp)which encodes 297 amino acids.The ELOVL2 protein contains 21 phosphorylation sites(13 serine,5 threonine and 3 tyrosine)and strong hydrophobic region.Its secondary structure is dominated by alpha-helix and random curl.The ELOVL5 gene has an open reading frame encoding 340 amino acids with a total length of 1023 bp.The ELOVL5 protein has 25 phosphorylation sites(12 serine,8 threonine and 5 tyrosine)and powerful hydrophilic region.Its secondary structure mainly consists extended chains and random curls.Both ELOVL2 and ELOVL5 proteins are stable non-secretory proteins which contain seven transmembrane domains and have no signal peptide sequence.The results of this study lay a foundation for the genetic evaluation of local varieties germplasm resources and the construction of technical platform for molecular breeding of local varieties.