高、低剩余采食量肉牛下丘脑组织中差异表达基因分析

Analysis of differential expression genes in hypothalamic tissue of beef cattle with high and low residual feed intake

为了分析高、低剩余采食量(residual feed intake,RFI)相关肉牛下丘脑组织中的基因表达图谱,探讨差异表达基因与牛RFI表型变异间的关系,试验选择高剩余采食量(HRFI)、低剩余采食量(LRFI)秦川牛各3头,分为HRFI组和LRFI组,采集下丘脑组织样本,从中提取总RNA进行转录组测序,筛选出RFI相关差异表达基因,对这些基因进行GO功能注释和KEGG通路富集分析,并利用STRING数据库构建差异表达基因的蛋白质相互作用网络图,最后随机选取6个差异表达基因进行实时荧光定量PCR验证。结果表明:HRFI组和LRFI组中均存在1538个差异表达基因,包括AGRP、PMCH等与采食相关的基因,GH1、MTNR1A和RYR2等与代谢相关的基因,此外差异基因主要富集于钙信号通路、cAMP信号通路和昼夜节律等通路中。通过蛋白质相互作用网络筛选出3个核心子网络和7个核心基因。实时荧光定量PCR验证结果与转录组测序结果一致。说明下丘脑组织中AGRP、PMCH、GH1、MTNR1A和RYR2等差异表达基因及钙信号通路、cAMP信号通路和昼夜节律等多条通路可能参与调控肉牛RFI。

The purpose of this study was to analyze the gene expression profiles in the hypothalamus of beef cattle related to high and low residual feed intake(residual feed intake,RFI),and to explore the relationship between the difference of gene expression and the phenotypic variation of bovine RFI.Three HRFI and three LRFI Qinchuan cattle were selected and divided into high residual feed intake(HRFI)group and low residual feed intake(LRFI)group.Hypothalamic tissue samples were collected and total RNA was extracted for transcriptome sequencing.RFI-related differential genes were screened and analyzed by GO functional annotation and KEGG pathway enrichment analysis.The protein interaction network map of differentially expressed genes was constructed by using STRING database.Finally,six differential genes were randomly selected for real-time fluorescence quantitative verification.The results showed that there were 1538 differentially expressed genes in HRFI group and LRFI group,including feeding-related genes such as AGRP and PMCH,and metabolism-related genes such as GH1,MTNR1A and RYR2.In addition,the differential genes were mainly enriched in calcium signal pathway,cAMP signal pathway and circadian rhythm.Three core subnetworks and seven core genes were screened by protein interaction network.RT-qPCR verification showed that the quantitative results were consistent with the sequencing results.It is indicated that the differential genes such as AGRP,PMCH,GH1,MTNR1A and RYR2 in hypothalamus and calcium signal pathway,cAMP signal pathway and circadian rhythm might be involved in the regulation of RFI in beef cattle.