Differential Proteome Analysis In Rib Eye Muscles Of Chinese Steppes Red And ChangBaiShan Blacks

Intramuscular fat (usually measured by meat marbling) is a major indicator of the juiciness and flavor of beef for both producers and consumers in most countries. It is a main contributor to meat quality but is affected by many factors, including breed, genotype, gender, age and nutrition.ChangBaiShan Blacks (Japanese Wagyu cattle×Chinese indigenous Yanbian Yellow cattle) and Chinese Red Steppes cattle (British Shorthorn cattle×local Inner Mongolia cattle×Limousin cattle) are two types of crossbred beef cattle. They have different fat deposition abilities, especially the intramuscular fat in ribeye muscle. Chinese Red Steppes cattle are a fast-growing breed of beef cattle compared with ChangBaiShan Blacks, but they have less intramuscular fat in the ribeye muscle.The objective of this study was to identify proteins that are differentially expressed in the Rib eye muscle of ChangBaiShan Blacks and Chinese Red Steppes cattle in the late intramuscular fat deposition stage using 2-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and mass spectrometry technology. The selected cattle were 32 months of age. On average, fat would already be deposited in the ribeye muscle at this stage. This study may provide a good basis for examining the molecular mechanisms involved in meat quality and investigate potential biomarkers for the intramuscular fat content of beef.The results suggest that the 27 differently expressed protein spots from ribeye muscle tissue were identified as 20 different proteins and validated by Western Blotting and quantitative real-time RT-PCR analyses. They are TNNT1,HBA,HBB,MYLPF,MYL1,MB,PGAM2,HSPB1,MYL6B,TPI,MSRA,TNNI2,TNNT3,TCAP,TXN,PSMA1,VDAC1,COX6B1,GSTM1 and GSTP1.Not all the proteins have the same expression in mRNA. HSPB1 and GSTP1 may have post-translational modification and alternative splicing after mRNA transcription.The differently expressed proteins were involved in metabolic processes, immune processes, cellular processes, myofiber growth, signaling, binding, transporter activity, catalytic activity, structural molecule activity and antioxidant activity during this stage. There were also some uncommon biological processes such as reproduction and death. We thus conclude that the fat deposition of cattle during this stage may be affected by the proteins that identified in 2D-DIGE in these pathways.