绵羊Fsp27基因组织表达、多态性及其与不同绵羊品种尾脂沉积能力的关联性分析

Tissue Expression Profiles and Polymorphism of Fsp27 Gene in Sheep ( Ovis aries ) and Their Association with Deposition of Tail Fat

旨在研究绵羊Fsp27基因的组织表达/多态性及其与不同绵羊品种尾脂沉积能力的关联性。本研究采用qRT-PCR检测了营养充足期阿勒泰羊不同组织中Fsp27基因的表达情况,同时对营养充足期和营养匮乏期阿勒泰羊尾脂组织中Fsp27基因的表达情况进行了定量分析,采用PCR-SSCP结合测序技术检测了5个不同尾脂沉积能力绵羊品种Fsp27基因的突变情况,并分析了相关突变与绵羊尾脂沉积能力的关联性。结果表明,Fsp27基因在营养充足期阿勒泰羊尾脂中高表达,其表达量极显著高于其他组织(P<0.01),在肾周脂肪和皮下脂肪组织中的表达量也较高,极显著高于心、肝、脾、肺、肾、胃、肠、皮肤和骨骼肌组织(P<0.01)。在心、肝、脾、肺、肾、胃、肠、皮肤和骨骼肌组织中呈微量表达,且各组织间差异不显著(P>0.05)。另外,营养充足期阿勒泰羊尾脂中Fsp27基因的表达量极显著高于营养匮乏期(P<0.01)。绵羊Fsp27基因在不同尾脂沉积能力品种群体中共检测到25个突变位点,其中位于第3外显子g. 16771741的G/A突变以及第5外显子g. 16774969的C/T突变均为错义突变,且与绵羊尾脂沉积能力高度相关。g. 16771741的G/A突变在尾脂沉积能力较强的阿勒泰羊、小尾寒羊和湖羊群体中以G等位基因为主,分别占到86.8%、83.7%和85.7%,而尾脂沉积能力较差的中国美利奴细毛羊和萨福克羊群体中G等位基因分别仅占30.3%和11.1%。g. 16774969的C/T突变在阿勒泰羊群体中以T等位基因为主,TT基因型占84.7%,CT基因型占15.3%,没有检测到CC基因型;在短脂尾型的小尾寒羊和湖羊群体中,TT和CT基因型也分别占到65.9%、50.4%和22.7%、41.1%,而在长瘦尾的中国美利奴细毛羊和萨福克羊群体中则以CC基因型为主,分别占到97.4%和69.4%,没有检测到TT基因型。以上研究结果表明,Fsp27基因在阿勒泰羊尾脂中高表达,且其在尾脂中的表达量与阿勒泰羊的营养状态密切相关,Fsp27基因第3外显子g. 16771741的G/A突变以及第5外显子g. 16774969的C/T突变与绵羊尾脂沉积能力高度相关,可以作为理想的分子标记用于低脂肪绵羊品种的选育。

The aim of this study was to investigate tissue expression profiles and polymorphism of Fsp27 gene in sheep(Ovis aries)and their association with tail fat deposition of different sheep breeds.The qRT-PCR was applied to detect the expression level of Fsp27 gene in different tissues of Altay sheep in adequate nutrition stage,and its expression levels in tail fat of Altay sheep in adequate and deficient nutrition stages,then the PCR-SSCP combined with sequencing were used to detect polymorphism of Fsp27 gene in 5 sheep breeds with different tail fat deposition ability and their association with tail fat deposition in sheep were analyzed.The results showed that Fsp27 gene was expressed at a high level in tail fat of Altay sheep in adequate nutrition stage and extremely higher than those in the other tissues(P<0.01),and expressed at a relatively high level in perirenal fat and subcutaneous fat which was extremely higher than those in heart,liver,spleen,lung,kidney,stomach,intestine,skin and skeletal muscle tissues(P<0.01),but expressed at a very low level in heart,liver,spleen,lung,kidney,stomach,intestine,skin and skeletal muscle tissues,and there were no significant difference among them(P>0.05).In addition,the expression level of Fsp27 gene in tail fat tissue of Altay sheep in adequate nutrition stage was significantly higher than that in deficient nutrition stage(P<0.01).Twenty-five SNPs were detected in Fsp27 gene sequence of sheep with different tail fat deposition ability,G/A mutation at g.16771741 site in exon3 and C/T at g.16774969 site in exon5 were missense mutations,and they were significantly associated with tail fat deposition ability of sheep.G was dominant allele in Altay sheep,Small Tail Han sheep and Hu sheep at g.16771741 site,the allele frequency was 86.8%,83.7%individuals and 85.7%,respectively,but only 30.3%and 11.1%individuals of Chinese Merino and Suffolk sheep were G allele at this site.T was dominant allele in Altay sheep at g.16774969 site,84.7%were TT genotype,15.3%individuals were CT genotype,and no CC genotype was detected,and the genotype frequency of TT and CT in Small Tail Han sheep and Hu sheep were 65.9%,50.4%and 22.7%,41.1%,respectively,but CC was dominant genotype in Chinese Merino and Suffolk sheep,their frequency were 97.4%and 69.4%,and no TT genotype was detected.These results indicated that Fsp27 gene expressed at a high level in tail fat tissue of Altay sheep,and its expression level was closely related with nutrition state of Altay sheep.The G/A mutation at g.16771741 site in exon3 and C/T mutation at g.16774969 site in exon5 of Fsp27 gene were highly correlated with tail fat deposition ability of sheep,so could be used to help selecting low fat sheep breed.