【摘要】 脂肪酸脱氢酶(fatty acid desaturases, FADS)在多不饱和脂肪酸的生物合成过程中起着非常重要的作用,其表达受到多种因素的影响。本研究利用生物信息学软件对鸡(Gallus gallus) FADS基因家族成员的共线性关系、亲缘进化关系、基因结构、保守基序和功能结构域进行系统的分析;采用实时荧光定量PCR (real-time quantitative PCR, qRT-PCR)技术对FADS基因家族成员的组织和时空表达规律进行分析,并通过活体实验分析了雌激素和营养因子对FADS家族成员基因表达的影响。研究结果显示,家禽中FADS3基因可能不存在或者未被注释,FADS1L1和FADS1L2基因仅存在于家禽中,FADS6基因所在染色体区段物种间较保守;FADS6基因在物种间单独聚为一支,FADS基因家族其他成员聚为一支;FADS6基因在物种间外显子数及保守基序的组成上与其他成员间存在较大差异;蛋白结构域预测结果显示,除FADS6外,鸡FADS1、FADS2、FADS1L1和FADS1L2基因编码蛋白中均存在相同功能结构域。组织时空表达分析显示,FADS家族各成员在鸡不同组织中均有表达,其中FADS1、FADS2和FADS6在肝脏中相对表达水平最高,FADS1L1在胸肌相对表达水平最高,FADS2L2在胰腺相对表达水平最高;FADS家族各成员在30周龄母鸡肝脏中的表达量均显著高于20周龄(P<0.05);17β-雌二醇处理实验结果表明,雌激素可显著上调鸡肝脏FADS1、FADS2和FADS1L1基因表达(P<0.05);基础日粮添加8%大豆油能够显著提高鸡肝脏FADS2基因表达(P<0.05)。本研究分析了FADS基因家族的生物学特性,以及雌激素和大豆油对其表达的影响,可为深入研究FADS基因家族作用机制提供基础资料。更多还原

【Abstract】 Fatty acid desaturases(FADS) play an important role in the biosynthesis of polyunsaturated fatty acids, and their expressions are affected by many factors. Bioinformatics softwares were used to systematically analyze the collinearity, phylogenetic relationship, gene structure, conserved motifs and functional domains of chicken(Gallus gallus) FADS gene family members. Real-time quantitative PCR(qRTPCR) was adopted to analyze the spatio-temporal expression of FADS gene family. The effects of estrogen and trophic factor on the expressions of the FADS gene family members in vivo were also investigated. The research results showed that FADS3 gene might not exist or annotated in poultry, while FADS1 L1 and FADS1 L2 were only found in poultry. The FADS6 located chromosome segment region was conserved among species. Phylogenetic analysis showed that the FADS6 genes of different species were clustered into one branch, and other members were clustered into another branch. The gene structure analysis and conserved motif analysis showed that the FADS6 gene was greatly different from other members of the family in exon number and the composition of conserved motif among species. The protein domain prediction results indicated that except FADS6, FADS1, FADS2, FADS1 L1 and FADS1 L2 genes owned the same functional structural domain. The tissues expression analysis showed FADS gene family members were widely expressed in different tissues. FADS1, FADS2 and FADS6 were relative highly expressed in the liver, FADS1 L1 in the pectoral muscle. and FADS2 L2 in the pancreas. The expression of FADS gene family in the liver of hens at the30-week-old was significantly higher than that at 20-week-old(P<0.05). In vivo assays displayed that 17β-estradiol could significantly up-regulate the expressions of FADS1, FADS2 and FADS1 L1 in chicken liver(P<0.05); and the addition of 8% soybean oil in the basal diet could significantly increase the expression of FADS2 in the chicken liver(P<0.05). In summary, this study comprehensively and systematically analyzed the biological characteristics of FADS gene family, and the effects of 17β-estradiol and soybean oil on their expressions which laid a foundation for further studying on the mechanism of FADS gene family.更多还原