Study On Genetic Relationship Of ADFP And PLIN Gene And The Growth And Development Of Fat Tissues In Chickens

Fatness traits were important factors of meat quality evaluation for high-quality chicken.The development of them would directly affect the economic value of high-quality chicken.Thus,it is necessary to study on the genes which control the development of fatness traits.Adipocyte differentiation-related protein and Perilipin were the phosphoprotein located on the surface of lipid droplet.The former researches reported ADFP and Perilipin controlled the lipid metabolism in human and mouse. Because both of them participated in the exceptional lipid metabolism of 2 type diabetes,adiposity and artery atherosclerosis,ADFP and Perilipin have been the study hotspot in medical field about two decades.The study results of ADFP and Perilipin in human and mouse were good references for study on the genetic mechanism of fatness traits in chickens.The current research adopted Sichuan Mountainous Land Black-Bone chicken as material.We successfully obtained the coding sequence of ADFP and PLIN gene, which were 1317bp and 1554bp.GenBank assigned them accession numbers EU620700 and EU620701,respectively.Based on these two cDNA sequences,we deduced two amino acid sequences.Their lengths were 438aa and 515aa.Via bioinformative analyses,we found both "the two amino acid sequences had the structure characters of PAT family and had high identity with ADFP and PLIN protein in other species,respectively.Thus,we concluded that they were the protein of chicken ADFP and PLIN.We inferred they had the function of controlling chicken lipid metabolism.The present study took Sichuan Mountainous Land Black-Bone chicken,Tibetan chicken and line S01 of Dahcng chicken as materials.We adopted the real-time PCR (SYBR greenⅠ) method to test the expression quantity of ADFP and PLIN genc in the breeds mentioned above at the first day and the 84^th day aider birth.And wc also tested the expression quantity of ADFP and PLIN genc in different growth points and had correlation analysis of these relative quantities and traits in Sichuan Mountainous Land Black-Bone chicken.The results indicated that ADFP and PLIN genc express in all tissues at all growth points,and there was advantageous tissue for gcnc expression at each growth point and there was also advantageous growth point for gene expression in a certain tissue.Furthermore,the developmental change of ADFP gene expression quantity in abdominal fat was positively related with the cumulative values of living weight and comb weight(P＜0.05),and the developmental change of ADFP genc expression quantity in breast muscle was positively related with the cumulative values of intramuscular fat content(P＜0.05).And the developmental change of PLIN gene expression quantity in abdominal fat was positively related with the cumulative values of subcutaneous fat thick(P＜0.05),and the developmental change of PLIN genc expression quantity in breast muscle was positively related with the cumulative values of intramuscular fat content(P＜0.05).The results indicated that the developmental change of ADFP and PLIN gene expression quantity were tightly correlated with the development change of fatness traits,especially with the development change of intramuscular fat content.Study on the ratioes of the expression quantity of ADFP gene and PLIN gene along with the growth points in Sichuan Mountainous Land Black-bone chicken discovered that the ratioes in subcutaneous fat and abdominal fat increased firstly and then deceased.So,we inferred that with adipocytes growing and being mature,ADFP and PLIN gcnc may have key role in turns in control chicken lipid metabolism.The current study adopted Mountainous Land Black-Bone chicken and Daheng high-quality chicken in Sichuan province,Huxu chicken,Xinghua chicken,Qingyuan ma chicken,and the cultivating line E2 and DC in Guangdong province,Xiayang chicken in Guangxi province,and one broiler breed,Arbor Acres chicken,totally 430 samples.We screened all the extrons and part ofintron sequences of ADFP gene and got three single nucleotide polymorphisms(SNP).They were located in the 4^th intron, the 5^th intron and the 8^th extron(at the 398^th amino acid position).The SNP1 was a transition of A to T at 33 394 913 in chromosome Z;the SNP2 was a transversion of C to T at 33 395 676 in chromosome Z;the SNP3 was a transversion of Ato G at 33 397 903 in chromosome Z.All the SNPs detected in the current study were novel and synonymous SNPs.The allele A,C and G were the predominant allele in SNP 1,SNP2 and SNP3,respectively.The results of single locus analysis showed that SNP3 had significant genetic effect on intramuscular fat content(P＜0.05);SNP1 had significant genetic effect on eviscerated weight,abdominal fat weight and percentage of abdominal fat(P＜0.05);and SNP2 had significant genetic effect on breast muscle weight,abdominal fat weight and subcutaneous fat thick(P＜0.05).The haplotype analysis indicated that the main haplotype combinations had significant genetic effect on breast muscle weight,abdominal fat weight and percentage of abdominal fat(P＜0.05).In a word,the polymorphisms of ADFP gene were significantly associated with carcass traits,especially the fatness traits.We inferred that ADFP gene probably was the major gene affecting fatness traits or was in linkage disequilibrium with the QTL controlling the fatness traits in chickens.We also found three SNPs in PLIN gene.They were located in extron 2(at the 7^th amino acid position) and extron 7(at the 285^th and the 289^th amino acid position).In chromosome 10,their positions were 14 521 351(T→C),14 523 391(C→T),14 523 402(G→A).All of them were synonymous but novel SNPs.There were no predominant allele at SNP1 and SNP2.However,allele G was the predominant allele at SNP3.And the SNP1 and SNP2 had middle polymorphic informative content(PIC). The single locus analysis indicated that SNP1(T/C),SNP2(C/T) and SNP3(G/A) had significant genetic effect on intramuscular fat content,breast muscle weight and carcass weight(P＜0.05).The haplotype analysis had significant genetic effect on subcutaneous fat thick(P＜0.05).Generally,the results of marker-trait linkage analyses indicated the polymorphisms of PLIN gene were significantly associated with carcass traits,especially the fatness traits.We inferred that PLIN gene probably was the major gene affecting fatness traits or was in linkage disequilibrium with the QTL controlling the fatness traits in chickens.