巴西橡胶树表观遗传研究进展

表观遗传是指在不涉及基因组DNA序列改变的情况下,基因功能发生了可逆的、可遗传的改变。研究表明,表观遗传调控在植物的生长发育及逆境胁迫应答反应中起着重要的作用。目前,表观遗传学研究主要集中在DNA甲基化、小RNA调控、组蛋白修饰、染色质重塑及基因组印迹等。与模式植物相比,橡胶树表观遗传的研究相对滞后,主要涉及DNA甲基化及miRNAs研究这2个方面。本文就橡胶树DNA甲基化及miRNAs的相关研究进行了简要综述,并对表观遗传在橡胶树中的研究前景提出展望。     

木薯 sRNA 测序分析及其开花相关 microRNA 的挖掘

为研究木薯花序与叶片中 sRNA 表达特性,探索 microRNA 对其开花过程的调控。本研究以木薯品种“华南 八号”花序和幼叶为材料,利用 RNA-seq 技术进行 sRNA 测序分析;并筛选开花相关 microRNAs 进行表达特性分析。 从花序和幼叶测序结果中分别获得 12 092 109 条和 11 499 655 条 sRNA 序列。花序中筛选出 139 条已知 microRNAs 和 253 条新预测 microRNA,分别预测得到 992 和 3 736 条靶基因;幼叶中筛选出 134 条已知 microRNA 和 191 条新预测 microRNAs,分别预测得到 979 和 2 603 条靶基因。最终筛选出 8 种与开花调控相关和 3 种花色调控相关的 microRNAs。 表达分析显示,miRNAs 在两样品间呈现出较大的整体性差异,并且在功能与代谢通路上也不尽相同;开花相关 microRNAs 中表达差异较大的为 miR156、miR172 和 miR169,其中 miR156 表达量在花序中高于幼叶,而 miR172 表 达量在花序中低于幼叶,推测其功能为抑制后续的开花过程,避免过度开花。本研究分析了木薯花序与幼叶中 sRNA 的整体特性,通过表达差异分析初步明确了 microRNAs 对木薯开花的调控,为进一步深入探索奠定了基础。     

Identification and Characterization of Drought Stress- Responsive Novel microRNAs in Dongxiang Wild Rice

MicroRNAs(miRNAs) are non-coding small RNAs, which play important regulatory roles in response to biotic and abiotic stresses. Dongxiang wild rice(Oryza rufipogon, DXWR) can survive in extreme drought environment, but its molecular mechanism of drought resistance is still largely unknown. To further explore miRNA regulatory mechanisms involved in drought resistance, we identified 138 novel miRNAs in DXWR using small RNA sequencing and bioinformatics approaches, and found that the expression levels of 67 novel miRNAs were significantly affected by drought stress. In total, 200 candidate target genes were predicted and annotated for the drought stress-responsive novel miRNAs. Gene Ontology(GO) analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathways suggested that most of the target genes were related to metabolism. Stem-loop quantitative real-time PCR(qRT-PCR) results exhibited high concordance with sequencing data, which confirmed that miRNA expression patterns based on small RNA sequencing in the present study were reliable. Meanwhile, qRT-PCR validated the inverse expression patterns between several miRNAs and their target genes. These results will enhance our understanding of miRNA regulatory mechanisms in response to drought stress in DXWR, and can serve as an important reference for the protection and utilization of this valuable genetic resource.     

非编码RNA调节羊绒细度候选基因的研究进展

羊绒细度是评价羊绒品质和衡量羊绒价格的关键数量性状,近年来,随着羊绒细度功能标记基因的深入研究,通过高通量数据解析及全基因组关联分析,逐步筛选出羊绒细度性状的候选基因,但是羊绒细度关键调控基因、表达量及分子调节机制尚未明了。基因表达受多种调节因子调控,其中非编码RNA的调节作用比较活跃,主要包括microRNA、lncRNA和circRNA等。经高通量测序和生物信息分析发现,非编码RNA在绒山羊品种间和品种内的不同羊绒细度个体皮肤、次级毛囊及次级毛囊周期性生长发育中差异表达并调节羊绒细度相关靶基因,但多种非编码RNA共同调节同一靶基因的信号通路甚少。目前通过对羊绒细度差异基因进行SNP标记辅助选择、转录组筛选、高通量解析非编码RNA调节及全基因组关联分析等相关研究发现,两两通路聚焦相同的羊绒细度靶基因较多,两条通路以上共同聚焦到某个或某几个羊绒细度的关键靶基因较少。作者主要讨论了羊绒细度候选基因及转录水平上microRNA、lncRNA和circRNA对羊绒细度相关靶基因分子调控机制的研究进展。     

Characterization of microRNA profile in mammary tissue of dairy and beef breed heifers

MicroRNAs (miRNAs) are small non‐coding RNAs that participate in the regulation of gene expression. Their role during mammary gland development is still largely unknown. In this study, we performed a microarray analysis to identify miRNAs associated with high mammogenic potential of the bovine mammary gland. We identified 54 significantly differentially expressed miRNAs between the mammary tissue of dairy (Holstein‐Friesian, HF) and beef (Limousin, LM) postpubertal heifers. Fifty‐two miRNAs had higher expression in the mammary tissue of LM heifers. The expression of the top candidate miRNAs (bta‐miR‐10b, bta‐miR‐29b, bta‐miR‐101, bta‐miR‐375, bta‐miR‐2285t, bta‐miR‐146b, bta‐let7b, bta‐miR‐107, bta‐miR‐1434‐3p) identified in the microarray experiment was additionally evaluated by qPCR. Enrichment analyses for targeted genes revealed that the major differences between miRNA expression in the mammary gland of HF versus LM were associated with the regulation of signalling pathways that are crucial for mammary gland development, such as TGF‐beta, insulin, WNT and inflammatory pathways. Moreover, a number of genes potentially targeted by significantly differentially expressed miRNAs were associated with the activity of mammary stem cells. These data indicate that the high developmental potential of the mammary gland in dairy cattle, leading to high milk productivity, depends also on a specific miRNA expression pattern.     

microRNA在反刍动物中的研究进展

微小RNA(microRNA,miRNA)是一类长度在22个核苷酸左右的小分子非编码RNA,通过与3'端非翻译区的碱基配对靶向调节mRNA的表达从而抑制其翻译或降解。miRNA广泛存在于动物和植物中,可以参与调节多种发育调控和生物学过程,本文在总结miRNA的来源、作用机制、预测方法及其基因表达与功能的基础上,综述了其在反刍动物中的研究进展。