绵羊FAM134B、PPARγ、HSL和FAS基因表达量及与肌内脂肪含量的关系

The FAM134B,PPARγ,HSL and FAS Gene Expression Patterns and Their Association with Intramuscular Fat Content in Sheep

旨在探究FAM134B、PPARγ、FAS和HSL基因在绵羊肌肉发育过程中的组织表达规律及其与肌内脂肪（Intramuscular fat,IMF）含量的关系,以期为研究绵羊IMF沉积的分子调控机制奠定理论基础。试验选取2、4、5、6和12月龄敖汉细毛羊公羊各5只,屠宰,采集背最长肌和股二头肌测定其IMF含量,应用实时荧光定量PCR技术检测PPARγ、FAM134B、FAS和HSL基因在肌肉不同发育时期的mRNA表达量,并对基因表达量之间及表达量与IMF含量的关系进行分析。结果表明：（1）2~5月龄时,背最长肌和股二头肌的IMF含量均随着月龄的增加而增加;而5~12月龄时则基本保持不变;同月龄背最长肌IMF含量极显著高于股二头肌（P〈0.01）。（2）背最长肌中FAM134B表达量呈上升-下降趋势,6月龄最高（P〈0.01）;股二头肌中FAM134B表达量呈先上升后稳定趋势。FAS基因在两部位肌肉中表达量均呈上升趋势。PPARγ基因在两部位肌肉中表达量均呈下降-上升趋势。HSL基因在两部位肌肉中表达量均呈下降-上升-下降趋势。同月龄目的基因表达量在两部位肌肉中均表现出明显的差异。（3）关联分析显示,两部位肌肉中FAM134B与FAS表达量均呈显著正相关（P〈0.05）,与PPARγ、HSL表达量呈不同程度负相关。背最长肌中,FAM134B、FAS表达量与IMF含量呈极显著或显著正相关（P〈0.01,P〈0.05）,PPARγ表达量与IMF含量显著负相关（P〈0.05）;股二头肌中,FAM134B表达量与IMF含量显著正相关（P〈0.05）。综上,FAM134B、FAS可能会促进IMF的沉积,而PPARγ、HSL对IMF的沉积可能具有抑制作用;FAM134B可能通过刺激脂肪合成基因的表达,而抑制脂肪分解基因的表达来调控IMF的含量。结果可为进一步解析相关基因的功能和调控IMF沉积的分子机制提供参考。

The objectives of this study were to investigate the developmental changes of FAM134 B,PPARγ,FASand HSLgene expression in the process of sheep muscles development and their association with intramuscular fat（IMF）accumulation,to lay a theoretical foundation for studying molecular regulation mechanism of the IMF deposition in sheep.Five Aohan finewool sheep were slaughtered at 2,4,5,6and 12 months old to collect samples fromlongissimus dorsi and biceps femoris,for the purpose of determining the IMF content.Then mRNA expression level of the FAM134 B,PPARγ,FASand HSL gene in different development period of muscles were analyzed by real-time PCR,and association between genes expression and IMF contents were analyzed.The results showed that：（1）Among 2-5months old,with growing of the age,the IMF contents of longissimus dorsi and biceps femoris were increasing.Among 5-12 months old,the IMF contents remained unchanged;The IMF content of longissimus dorsi were extremely significantly higher than biceps femoris（P〈0.01）at the same age.（2）In longissimus dorsi,FAM134 Bexpression level presented first increased and then declined with growing,the highest was in 6months old（P〈0.01）.In biceps femoris,FAM134 Bexpression level presented increased and then stabilized with growing.FASexpression level increased with growing in both of two parts of muscles.PPARγexpression level presented first declined and then increased with growing.HSLexpression levels was showed ＂declined-increased-declined＂patterns in two parts of muscles.In the same month,target genes expression level had tissue-dependent in two parts of muscles.（3）Correlation analysis showed that the expression level of FAM134 B was significantly positively related to FASin two parts of muscles（P〈0.05）,and was negatively related to PPARγand HSLexpression levels at different levels.In longissimus dorsi,FAM134 B,FAS expression levels were significantly positively related to IMF content（P〈0.01 or P〈0.05,respectively）,PPARγexpression level was significantly negatively related to IMF content（P〈0.05）.In biceps femoris,FAM134 Bexpression level was significantly positively correlated with the IMF content（P〈0.05）.In conclusion,FAM134 B,FASexpression might have positively effect on IMF accumulation,and PPARγ,HSLexpression might have negatively effect on IMF accumulation.FAM134 B was likely to regulate IMF content through stimulating expression level of fat synthetic genes and inhibiting adipose decompose genes.The results would provide reference for studying related gene functions and molecular mechanism of the IMF deposition.