安格斯牛和南阳牛肌内脂肪组织中差异表达circRNAs分析

Differential expression of circRNAs in intramuscular adipose tissue of Angus cattle and Nanyang cattle

【目的】筛选牛肌肉脂肪组织中差异表达的circRNAs,为进一步探索circRNAs在牛肌内脂肪沉积和代谢过程中的潜在作用及肉牛改良提供理论基础。【方法】采集安格斯牛和南阳牛右侧背部最长肌第12/13肋骨间肌肉,分离其脂肪组织并提取RNA,采用RNA-seq和生物信息学方法分析2种牛肌内脂肪组织中circRNAs的表达情况,筛选差异表达的circRNAs,并对其进行GO和KEGG富集分析。选取4个差异表达的circRNA(circRNA.9560、circRNA.7431、circRNA.2083、circRNA.6528),对其表达水平进行qRT-PCR验证。【结果】在所有牛样本肌内脂肪组织中共检测到14649个circRNAs,从中筛选并初步鉴定出111个安格斯牛与南阳牛差异表达的circRNAs,其中有75个在安格斯牛肌内脂肪组织中表达上调,36个表达下调。差异表达的circRNAs主要富集于细胞进程、单有机体进程、代谢过程、细胞、细胞部分、细胞器、分子结合、催化活性、核酸结合转录因子活性的GO条目中。KEGG富集分析结果发现,差异表达的circRNAs共富集到66条信号通路中,其中具有显著差异(P<0.05)的信号通路有10个。qRT-PCR验证结果显示,circRNA.9560和circRNA.7431表达量显著下调,circRNA.2083和circRNA.6528表达量显著上调,与测序结果一致。【结论】筛选出111个安格斯牛与南阳牛差异表达的circRNAs,这些circRNAs可能在牛脂肪沉积和脂质代谢过程中发挥着一定的调控作用。

【Objective】This study screened the differential expression of circRNAs in bovine intramuscular adipose tissue to provide basis for further exploring the potential role of circRNAs in deposition and metabolism of intramuscular adipose tissue in bovine and improving beef cattle.【Method】In this study,the 12th/13th intercostal muscle of long intramuscular on the right side back of Angus cattle and Nanyang cattle was collected.The intramuscular adipose tissue was separated and RNA was extracted,then the RNA was analyzed by RNA-seq and bioinformatics.The differential expression of circRNAs in the tissues was screened for GO and KEGG enrichment analysis.Four differentially expressed circRNAs(circRNA.9560,circRNA.7431,circRNA.2083 and circRNA.6528)were selected and their expression levels were verified by qRT-PCR.【Result】A total of 14649 circRNAs were detected,and 111 differentially expressed circRNAs were screened and identified.Among them,75 were up-regulated in Anger’s intramuscular adipose tissue and 36 were down-regulated.The differentially expressed circRNAs were mainly enriched in the GO terms including cellular process,single-organism process,metabolic process,cell,cell part,organelle,catalytic activity,molecular binding and nucleic acid.KEGG enrichment analysis showed that differentially expressed circRNAs were enriched to 66 signal pathways,and 10 of them were very different(P<0.05)expressed between Nanyang cattle and Angus cattle.Four differentially expressed circRNAs were selected for qRT-PCR validation.The results showed that circRNA.9560 and circRNA.7431 were significantly down-regulated,while circRNA.2083 and circRNA.6528 were significantly up-regulated,which were consistent with the sequencing results.【Conclusion】111 differentially expressed circRNAs were screened between Anger cattle and Nanyang cattle.The differentially expressed circRNAs may play a regulatory role in cattle fat deposition and lipid metabolism.