Rotavirus gene silencing by small interfering RNAs

RNA interference is an evolutionarily conserved double-stranded RNA-triggered mechanism for suppressing gene expression. Rotaviruses, the leading cause of severe diarrhea in young children, are formed by three concentric layers of protein, from which the spike protein VP4 projects. Here, we show that a small interfering RNA corresponding to the VP4 gene efficiently inhibits the synthesis of this protein in virus-infected cells. A large proportion of infected cells had no detectable VP4 and the yield of viral progeny was reduced. Most of the virus particles purified from these cells were triple-layered, but lacked VP4, and were poorly infectious. We also show that VP4 might not be required for the last step of virus morphogenesis. The VP4 gene silencing was specific, since the synthesis of VP4 from rotavirus strains that differ in the target sequence was not affected. These findings offer the possibility of carrying out reverse genetics in rotaviruses.     

Noncoding RNAs within the HOX gene network in tumor pathogenesis and progression

HOX genes are involved with normal development, cell identity, cell differentiation, cell metabolism, apoptosis, autophagy as well as with diseases such as tumor pathogenesis and progression. In particular, the genes belonging to HOX paralogous 13 seem to carry out a relevant role in both tumor development and disease progression. In recent years, several noncoding RNAs (ncRNA) sequences have been identified in HOX loci, including long noncoding RNA (lncRNA) and microRNA (miRNA), highly conserved during evolution. Many studies have shown that specific intergenic ncRNAs in HOX loci could directly modulate HOX genes expression in normal and pathological conditions. In the present review we attempt to describe the role of these ncRNAs, through the regulation of the HOX gene network, in normal cell biology, and, with particular emphasis, in diseases such as in cancer pathogenesis and progression.     

Structural diversity repertoire of gene silencing small interfering RNAs

Since the discovery of double-stranded (ds) RNA-mediated RNA interference (RNAi) phenomenon in Caenorhabditis elegans, specific gene silencing based upon RNAi mechanism has become a novel biomedical tool that has extended our understanding of cell biology and opened the door to an innovative class of therapeutic agents. To silence genes in mammalian cells, short dsRNA referred to as small interfering RNA (siRNA) is used as an RNAi trigger to avoid nonspecific interferon responses induced by long dsRNAs. An early structure-activity relationship study performed in Drosophila melanogaster embryonic extract suggested the existence of strict siRNA structural design rules to achieve optimal gene silencing. These rules include the presence of a 3' overhang, a fixed duplex length, and structural symmetry, which defined the structure of a classical siRNA. However, several recent studies performed in mammalian cells have hinted that the gene silencing siRNA structure could be much more flexible than that originally proposed. Moreover, many of the nonclassical siRNA structural variants reported improved features over the classical siRNAs, including increased potency, reduced nonspecific responses, and enhanced cellular delivery. In this review, we summarize the recent progress in the development of gene silencing siRNA structural variants and discuss these in light of the flexibility of the RNAi machinery in mammalian cells.     

长非编码RNA研究进展

长非编码RNA是指一类长度大于200个核苷酸、不编码蛋白质的非编码RNA.越来越多的研究表明,人类基因组中高达90%的非编码蛋白质的区段同样具有重要作用,而不是所谓的"转录噪声".针对长非编码RNA的功能研究表明,其在转录起始的调控、转录及转录后的调控中均发挥着重要作用,因而影响着各种各样的生物学过程.本综述围绕近几年长非编码RNA的研究成果,总结了长非编码RNA的起源与进化、新型的长非编码RNA类型、典型的长非编码RNA作用机制以及长非编码RNA在发育与细胞重编程过程中的研究,同时也概述了长非编码RNA与表观遗传调控和癌症的关系以及长非编码RNA研究的相关技术.系统发现长非编码RNA并阐明其功能机制,将对现代生命科学具有重大的意义.     

Noncoding RNAs in alcoholic liver disease

Alcoholic liver disease (ALD) is a complex process with high morbitity and can cause liver dysfunction, which contains a wide spectrum of hepatic lesions, including steatohepatitis, fibrosis, cirrhosis, and eventually hepatocellular carcinoma. To date, the molecular mechanisms for ALD have not been fully explored and an effective therapy is still missing. Overwhelming evidence shows dysregulation of noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs), is correlated with etiopathogenesis and progress of ALD including hepatocyte damage, disrupted lipid metabolism, aggressive inflammatory responses, oxidative stress, programmed cell death, fibrosis, and epigenetic changes induced by alcohol. For example, circulating miRNA-122 is a marker of hepatocyte damage, and miRNA-155 is a potential marker of inflammation, indicating their diagnosis therapeutic potential in ALD. In addition, roles for long noncoding RNAs (lncRNAs) and circular RNAs in ALD are being uncovered. Further, circulating ncRNAs and exosome-derived ncRNAs have attracted more attention lately, suggesting a role in the prevention and treatment of ALD. This review covers the roles of ncRNAs in ALD, and the potential uses as markers for diagnosis and therapeutic options.     

Noncoding RNAs in acute kidney injury

Acute kidney injury (AKI), caused by various stimuli including ischemia reperfusion, nephrotoxic insult, and sepsis, is characterized by abrupt decline of kidney function. Till now, the molecular mechanisms for AKI have not been fully explored and the effective therapies are still lacking. Noncoding RNAs (ncRNAs), a group of biomolecules function at RNA level, are involved in a wide range of physiopathological processes including AKI. MicroRNAs (miRNAs) are the most extensively studied ncRNAs in AKI. Evidence indicated that miRNAs are altered significantly in various types of AKI. Gain-and-loss-of-function studies demonstrated that miRNAs, such as miR-24, miR-126, miR-494, and miR-687, may bind to the 3′-untranslated region of their target genes to regulate inflammation, programmed cell death, and cell cycle in the injury and repair stages of AKI, indicating their therapeutic potential in AKI. In contrast, functions of long noncoding RNAs and circular RNAs in AKI are hot topics but still largely unknown. Additionally, ncRNAs packaged in exosome can be detected in circulation and urine, they may serve as specific biomarkers for AKI. This review summarized the alteration and functional role of ncRNAs and their therapeutic potential in AKI.     

N-myc 蛋白和非编码RNA在神经母细胞瘤中的研究进展

神经母细胞瘤是儿童外周神经系统的肿瘤。在近20%的神经母细胞瘤病例中发现有原癌基因MYCN的扩增和过表达现 象。近几年发现MYCN基因编码的N-myc 蛋白,不仅能够调控多种非编码RNA 的表达,而且也受非编码RNA的调控。miRNA 是在神经母细胞瘤中研究最广泛的非编码RNA,近年来研究发现N-myc 蛋白对于绝大部分miRNA 起抑制作用,如mir-184、 mir-542-5p 等,仅对少数miRNA起诱导表达的作用,如mir-17-92 基因簇、mir-9、mir-421 等。N-myc 蛋白不仅对miRNA 的表达起 调节作用,而且也调控其它lncRNA 的表达,如T-UCR、NDM29、linc00467、MALAT1。有趣的是,N-myc 蛋白和miRNA 之间的作 用是相互的,它们可以双向调节,其调控网络也是复杂的。miRNA 能够靶向MYCN,同时MYCN也能够调控miRNA。该文对神 经母细胞瘤中N-myc蛋白和非编码RNA 间的相互影响,以及两者之间的关系对神经母细胞瘤的发生有何作用作一综述。