The Study Of Molecular Mechanism Of Muscle Growth And Intra-Muscular Fat Deposition In Beijing-You Chickens With Proteomics Techniques

Muscle development is a key component for efficiency of poultry meat production, and intramus-cular fat (IMF) content is an important factor for meat quality. In current study, we carried out studies on the expression profiling of protein in breast muscle of Beijing-You chicken (BJY) at different stages by isobaric tags for relative and absolute quantitation (iTRAQ). The molecular mechanism of fat me-tabolism and the muscle growth were explored. Three trails were included:Trial1:The study of the differentially expressed proteins in breast muscle of BJY at different stag-es by proteomics techniques. Forty BJY chickens (female) hatchlings were randomly assigned to four groups. At each age of day1(d, day of hatchling), d56(rapid growth age), d98(marketing age) and d140(sexual maturity), one group of chicken (10birds) were weighed and killed. The protein mixed pools of breast tissues were built at different ages and used in the iTRAQ analysis after the total protein of muscle samples was extracted. The results showed that:1) A total of517proteins were identified, in which494were quantitative;210proteins were down-regulated and210were up-regulated.2) The most similar expression patterns of proteins were acquired in breast muscle between d56and d98, the most difference were among hatching and the rest ages by cluster analysis.Trial2:Study of the differentially expressed proteins and molecular mechanism related to muscle growth in breast muscle of BJY. Birds used are as same as trail1. Some important proteins (all proteins come from of Trial1) and pathway are selected by bioinformatics analysis or correlation analysis for iTRAQ date and breast carcass, and verified by WB. The results showed that:1)the fast stage form d1to d98were main stage for the muscle development.2) GYG1、HNRNPK, LOC418811、MDH1pfk、 ANXA2、CAPNS1、CFL2、PDLIM3、MYOZ3were found to be key proteins involved in muscl growth.3) Through KEGG pathway analysis and previous researches. From d1to d56:①CALM, CAPNs, TTN, TnC were activated by the second messenger Ca2+, then expression of f cytoskeleton pro-teins and muscle contraction increased.②Expression of the ubiquitin-proteasome system protein high in post-hatching, many proteins in cell were degradation, so that muscle cell hypertrophy.4) From d56to d98:①The cytoskeleton proteins increased and muscle hypertrophy on the conditions of focal adhe-sion, tight juntion, the regulation of the actin cytoskeleton and hypertrophic cardiomyopathy were regu-lated by ECM matrix.②actin cytoskeleton and cell adhesion were promoted by ANXA2increased, fur-thermore, muscle contractions strengthened because that DES decreased and the pull of sarcomere was restrained, muscle contraction lead to muscle cell hypertrophy.5) In summary, focal adhesion, hyper-trophic cardiomyopathy and dilated cardiomyopathy were identified to be important pathways influenc-ing the muscle development. ubiquitin-proteasome system, Ca2+_CALM, annexin and ECM matrix were found to influence muscle development.Trial3:Study of the differentially expressed proteins and molecular mechanism related to IMF me-tabolism in breast muscle of BJY. Birds used are as same as trail1. Some important proteins (all pro- teins come from of Trial1) and pathway are selected by bioinformatics analysis or correlation analysis for iTRAQ date and lipid content in breast, and verified by WB. The results showed that:1) The IMF in the liver, breast muscle, leg muscle were significantly higher in hatching than that in after hatching (P<0.05), and the accumulation of fat in the liver, breast muscle, leg muscle increased significantly after56days (P<0.05).2) ACAA2, APOA1, ANXA2, RAB5C were consistent to be the pivotal proteins in-volved in lipid metabolism on basis of two analysis.3) The molecular mechanisms for lipid metabolism were different in different developmental stages. From hatching to d56, it indicated that IMF deposition from hatching to56days was due to fat synthesis, proliferation and differentiation of adipocytes in breast muscle. From d56to d98, it indicated that annexin and focal adhesion, tight junction, the regula-tion of the actin cytoskeleton and hypertrophic cardiomyopathy were regulated by ECM affected major on lipid metabolism. From d98to d140, and it indicated that the fat deposition because of lipid was transported from liver by APOA1and the oxidation capacity of fatty acid was decreased in breast mus-cle.4) In summary, Fatty acid metabolic and PPAR signaling pathway played a key role in IMF metabo-lism, ANXA2andM-receptor interaction, right junction, focal adhesion and regulation of actin cyto-skeleton played important roles in IMF deposition on the basis of information analysis and previous researches.In conclusion, ACAA2, ANXA2, GYG1, MDH1, PFK, LOC418811were identified to be key pro-teins in regulating muscle development and lipid metabolism; annexin, ECM matrix, the signal path-ways (focal adhesion, right junction, the regulation of actin cytoskeleton, hypertrophic cardiomyopathy) mediated by ECM were the key molecular pathways for muscle development and IMF deposition.