NELL1和 FMO3基因mRNA在绵羊肝脏与脂肪组织中的表达
mRNA Expression of NELL1 and FMO3 in Liver and Adipose Tissue of Sheep

旨在探究不同营养水平及不同生长阶段脂尾型绵羊 NELL1和 FMO3基因mRNA的组织特异性表达模式。选择健康、体质量相近的9月龄滩羊、同羊、哈萨克羊和西藏羊(羯羊)各3只，活体采集尾部脂肪样品。选择健康4月龄滩羊112只随机分为4组，公母各半，每组 4 个重复，每个重复7只羊。根据体质量增加目标分为3个阶段：22~28 kg，28~35 kg，35~40 kg，每个阶段各组分别饲喂不同营养水平的日粮。每个生长阶段结束时采集肝脏、肾周脂肪、尾脂、皮下脂肪的组织样品，提取样品总RNA，采用实时荧光定量PCR的方法分析 NELL1和 FMO3mRNA的表达差异。结果表明， FMO3 mRNA在哈萨克羊尾脂中的表达量最高，在同羊、滩羊、西藏羊尾脂中依次下降，且差异显著； NELL1 mRNA在西藏羊尾脂中的表达量最高，在滩羊、同羊、哈萨克羊中的表达量依次下降；营养水平和月龄对尾脂和肝脏中 NELL1和 FMO3mRNA的表达水平有显著影响，而对皮下脂肪和肾周脂肪中 NELL1和 FMO3mRNA的表达影响不显著。表明 FMO3 mRNA的表达水平与脂肪沉积呈正相关，而 NELL1 mRNA的表达水平与脂肪沉积呈负相关； NELL1与 FMO3对绵羊尾脂和肝脏中的脂肪沉积起调控作用，为进一步揭示脂尾型绵羊体内脂肪沉积的调控机制提供理论基础。
This experiment was to explore the tissue specific expession of NELL1 and FMO3 in fat-tailed sheep under different nutrition levels and in different growth periods. Firstly,nine-month-aged Tan sheep,Tong sheep,Kazakh and Tibetan sheep which had the similar body mass were selected for adipose tissue collection,three individuals were used for each breed. In total,112 healthy Tan sheep were randomly divided into four groups (according to a completely random experiment design) with four replicates per group (two males and two females),each replicate comprises seven animals. This experiment was divided into three periods according to mass gain target:22-28 kg,28-35 kg,35-40 kg. At the end of each stage,the liver fat,perineal fat,tail fat and subcutaneous fat were collected. The total RNA was extracted from adipose tissues,and the expression level of FMO3 and NELL1 were analyzed by quantitative PCR. The results showed as that: the highest expression level of FMO3 was in the Kazakh breed (fat-tailed),followed by Tong,Tan,and Tibetan sheep (short-tail). In addition, NELL1 is highly expressed in the tails of Tibetan sheep,declined in turn with Tan sheep,Tong sheep,and Kazakh breed. The expression of FMO3 and NELL1 in liver and tail fat were significantly affected by nutrition levels and ages,while there was no detectable influence in perineal and subcutaneous fat. In conclusion,fat deposition had a positive correlation to FMO3 expression and negatively correlated to NELL1 expression in sheep. The effects of FMO3 and NELL1 on fat deposition may be regulated through their expression difference in liver and tail fat. Our results provide molecular basis to illustrate the mechanism of fat deposition in fat-tailed sheep breeds.