Herpesviruses throw a curve ball: new insights into microRNA biogenesis and evolution

  title={Herpesviruses throw a curve ball: new insights into microRNA biogenesis and evolution},
  author={Joel R Neilson and Phillip A. Sharp},
  journal={Nature Methods},
Validation and comparison of previously unknown microRNA genes in related herpesviruses yielded several surprises, most notably in regard to viral evolution and microRNA biogenesis. An explosion of literature has recently appeared describing the identification and mechanism of action of microRNAs (miRNAs)—small RNA regulators of gene expression in plant and animal cells. 
Discoveries and functions of virus-encoded MicroRNAs
This review provides background information on the history of virally encoded miRNAs including their genomic distribution, functions and mechanisms and the future directions of researches in viral mi RNAs and their applications in diseases control and therapy.
Mouse Cytomegalovirus MicroRNAs Dominate the Cellular Small RNA Profile during Lytic Infection and Show Features of Posttranscriptional Regulation
The identification and characterization of 18 viral miRNAs from mouse fibroblasts lytically infected with the murine cytomegalovirus (MCMV) and polyuridylation of their 3′ end, coupled to subsequent degradation are observed.
MicroRNA: past and present.
Improved software programs are now able to predict the targets of miRNAs in a more efficient manner, thus facilitating the elucidation of miRNA function, and methods such as real-time PCR and microarray have been enhanced for studying miRNA expression.
Mechanisms Involved in Symptom Modulation by Turnip Crinkle Virus and its Associated Subviral RNAs
The results suggest that at least some vsRNAs are specifically altering expression of host genes leading to phenotypic changes in host plants, which should be amenable for detection of any virus with a transformable host.
Widespread evidence of viral miRNAs targeting host pathways
It is shown that for several of the 135 known viral miRNAs in human viruses, the human genes targeted by the viral miRNA are enriched for specific host pathways whose targeting is likely beneficial to the virus.
Identification and Analysis of Expression of Novel MicroRNAs of Murine Gammaherpesvirus 68
By deep sequencing of small RNAs, this work systematically investigated the expression profiles of MHV-68 miRNAs and found that mmu-mir-15b and mmu -mir-16 are highly upregulated upon MHV’s infection of NIH 3T3 cells, indicating a potential role for cellular miRNA expression signatures during MHv-68 infection.
Malignant Catarrhal Fever of Cattle Is Associated with Low Abundance of IL-2 Transcript and a Predominantly Latent Profile of Ovine Herpesvirus 2 Gene Expression
The phenotype of mice with a deficient IL-2-system almost perfectly matches the clinical signs observed in cattle with MCF, which supports the hypothesis that immunopathogenic events are linked to the pathogenesis of MCF.
Measuring kinase activity: finding needles in a haystack
New fluorescent peptide–based reporters provide a means for following kinase activity in crude cell extracts and help clarify the role of EMT in cell reprograming.
On the rules of co-existence between sheep, cattle, and OvHV-2
The cell populations targeted by the virus during natural infection of lambs were analyzed and the gene expression patterns of OvHV-2 and the relative abundances of host cell transcripts in lymphocytes of diseased cattle were tested to identify pathways possibly involved in the pathogenesis of MCF.


Identification of Virus-Encoded MicroRNAs
The small RNA profile of cells infected by Epstein-Barr virus is recorded and it is shown that EBV expresses several microRNA (miRNA) genes, which are identified viral regulators of host and/or viral gene expression.
Identification of microRNAs of the herpesvirus family
To identify other miRNA genes in pathogenic viruses, a new miRNA gene prediction method with small-RNA cloning from several virus-infected cell types was combined and predicted miRNAs in several large DNA viruses.
Molecular evolution of the Herpesvirinae
This paper examines four topics: (i) the phylogeny of the Herpesvirinae; (ii) the histopathology of the group; (iii) the molecular phylogenies of the groups; and (iv) the role of parasites in the group's evolution.
Human microRNAs are processed from capped, polyadenylated transcripts that can also function as mRNAs.
Together, these data show that human pri-miRNAs are not only structurally similar to mRNAs but can, in fact, function both as pri- miRNAs and m RNAs.
MicroRNA genes are transcribed by RNA polymerase II
The first direct evidence that miRNA genes are transcribed by RNA polymerase II (pol II) is presented and the detailed structure of a miRNA gene is described, for the first time, by determining the promoter and the terminator of mir‐23a∼27a‐24‐2.
Microarray analysis shows that some microRNAs downregulate large numbers of target mRNAs
These results suggest that metazoan miRNAs can reduce the levels of many of their target transcripts, not just the amount of protein deriving from these transcripts, and seem to downregulate a far greater number of targets than previously appreciated.
The 21-nucleotide let-7 RNA regulates developmental timing in Caenorhabditis elegans
It is shown that let-7 is a heterochronic switch gene that encodes a temporally regulated 21-nucleotide RNA that is complementary to elements in the 3′ untranslated regions of the heteroch chronic genes lin-14, lin-28, Lin-41, lin -42 and daf-12, indicating that expression of these genes may be directly controlled by let- 7.
N at ur e P u b lis hi ng G ro up ht tp :// w w w .n at ur e
  • Cell 120,
  • 2005