The miRNA world of polyomaviruses
© Lagatie et al.; licensee BioMed Central Ltd. 2013
Received: 11 July 2013
Accepted: 27 August 2013
Published: 28 August 2013
Polyomaviruses are a family of non-enveloped DNA viruses infecting several species, including humans, primates, birds, rodents, bats, horse, cattle, raccoon and sea lion. They typically cause asymptomatic infection and establish latency but can be reactivated under certain conditions causing severe diseases. MicroRNAs (miRNAs) are small non-coding RNAs that play important roles in several cellular processes by binding to and inhibiting the translation of specific mRNA transcripts. In this review, we summarize the current knowledge of microRNAs involved in polyomavirus infection. We review in detail the different viral miRNAs that have been discovered and the role they play in controlling both host and viral protein expression. We also give an overview of the current understanding on how host miRNAs may function in controlling polyomavirus replication, immune evasion and pathogenesis.
KeywordsPolyomaviruses microRNAs Virus-host interaction Immune evasion
Simian virus 40
Progressive multifocal leukoencephalopathy
Merkel cell carcinoma
Merkel cell virus
Trichodysplasia spinulosa-associated Polyomavirus
Non-coding control region
Large T (tumor) antigen
Small T antigen
RNA-induced silencing complex
Cytotoxic T lymphocytes
UL16-binding protein 3
Natural killer group 2, member D
Herpes viruses human cytomegalovirus
Kaposi's sarcoma-associated herpesvirus
MHC class I chain-related protein B
Bandicoot Papillomatosis Carcinomatosis virus
Human immunodificiency virus-1
Hepatitis C virus
Lymphocytic choriomeningitis virus.
General overview of polyomaviruses
Polyomaviruses comprise a family of DNA tumor viruses. They are non-enveloped and have a circular, double stranded DNA genome of around 5,100 bp . The virion consists of 72 pentamers of the capsid protein VP1 with a single copy of VP2 and VP3 associated to each pentamer [2, 3]. Although originally categorized together with the Papillomaviridae under the designation of Papovaviridae, they were separated in 2000 by the International Committee on Taxonomy of Viruses to become two distinct families [4, 5]. The first polyomavirus family member, murine polyomavirus (MuPyV), was discovered as a tumor agent in mice already in 1958, shortly followed by the first primate polyomavirus, Simian Virus 40 (SV40), which was discovered in 1960 [6, 7]. Since the discovery of the first two human polyomaviruses, JC Virus (JCPyV) and BK Virus (BKPyV) in 1971, several new members of the polyomavirus family have been identified [8, 9]. To date, complete genome reference sequences for 46 polyomaviruses have been deposited at Genbank. Of those, 12 are human polyomaviruses [10–13]. Several polyomaviruses have been associated to specific diseases, such as Progressive Multifocal Leukoencephalopathy (PML) for JCPyV, polyomavirus-associated nephropathy (PVAN) for BKPyV, Merkel cell carcinoma (MCC) for Merkel Cell Virus (MCPyV) and trichodysplasia spinulosa for Trichodysplasia spinulosa-associated Polyomavirus (TSPyV) [4, 10, 11, 14–20]. One of the most striking observations is the fact that asymptomatic infection occurs during childhood which is followed ordinarily by life-long asymptomatic persistence . It remains however puzzling how this latency state is changed into a reactivated state upon changes in the host immune system in some individuals.
Biogenesis and function of microRNAs
MicroRNAs (miRNAs) are RNAs of 20–23-nucleotide (nt) length that play a key role in several cellular processes. These non-coding RNAs typically silence gene expression by directing repressive protein complexes to the 3′ untranslated region (3′UTR) of target mRNA transcripts. Although originally discovered in the nematode C. elegans, they have been found to be expressed in several organisms, such as insects, nematodes, plants, humans and viruses [42–46]. Of particular interest is the role these small RNAs play in regulation of the innate immune response, adaptive immune cell differentiation, metabolism, apoptosis, cell proliferation, cancer and maintenance of homeostasis during stress [43, 47].
MiRNAs are derived from longer precursor primary transcripts (pri-miRNAs) that are typically transcribed by RNA polymerase II (Pol II), which also is responsible for transcription of mRNAs. These pri-miRNAs contain at least one imperfect stem-loop hairpin structure and this hairpin structure is processed in the nucleus via the RNAse III-like endonuclease Drosha . The newly formed ~60 nt hairpin, called pre-miRNA is exported from the nucleus into the cytosol via the RAN-GTPase Exportin-5 [49, 50]. In the cytoplasm, this pre-miRNA is recognized and cleaved by the RNAse III-like endonuclease Dicer resulting in an RNA duplex, typically having short (~2nt) 3′ overhangs [51, 52]. One of the two strands of this ~22nt duplex RNA, called the miRNA or “guide” strand is loaded into the multiprotein RNA-induced silencing complex (RISC). The other strand, called the “star” (*) or “passenger” strand is energetically less favored to enter RISC and is therefore typically found at lower steady state levels. A key component of RISC is the Argonaute (Ago) protein, which associates with the guide strand, thereby directing the complex to the target sequence through Watson-Crick base pairing [51–53]. MiRNA binding sites are usually located in the 3′ UTR and are often present in multiple copies. Most animal miRNAs bind imperfectly with the target mRNA, although a key feature of recognition involves base-pairing of miRNA nucleotides 2–8, representing the seed region . The degree of miRNA-mRNA complementarity is a key determinant of the further process. Perfect or near perfect complementarity may lead to Ago-catalyzed cleavage of the mRNA strand, whereas imperfect complementarity leads to translational repression, which is thought to be the default mechanism by which miRNAs repress gene expression [54–56]. Although multiple Argonaute proteins are present in mammals, only Ago2 is shown to have mRNA cleavage activity .
Polyomaviruses encoded miRNAs
microRNAs in polyomaviruses
miRBase V20 Accession No.
Genomic location (nt position in reference sequence)
3′ end LTAg (2682–2767 in NC_001699.1)
LTAg, stAg2 ULBP3
3′ end LTAg (2808–2909 in NC_001538.1)
3′ end LTAg (2776–2863 in NC_001669.1)
LT, stAg DMWD2, C20orf272
3′ end LTAg (2786–2869 in NC_007611.1)
5′ end LTAg (1168–1251 in JN383838.1)
LTAg1 AMBRA22, RBM92, MECP22, PIK3CD2, PSME23 and RUNX22
5′ end LTAg (1137–1269 in NC_001515.1)
LTAg, MTAg, stAg
between the 3′ ends of the T-antigens and L1/L2 (4917–4987 in NC_010107.1)
between the 3′ ends of the T-antigens and L1/L2 (no reference available)
The closely related polyomaviruses JCPyV, BKPyV, SV40, and SA12 have been shown to encode a single pre-miRNA that maps to the late strand of the viral genome and is found downstream of the late polyadenylation (pA) site (Figure 1A) [62–66]. The mature miRNAs are located at the 3′end of the second LTAg exon, which is transcribed in the viral early transcript and the miRNAs are therefore completely complementary to the early mRNA. As would be predicted based on this property, it was shown for SV40 that the miRNAs direct cleavage of this early mRNA resulting in reduced protein expression of LTAg and stAg . Although there is very high sequence similarity among the miRNAs encoded by JCPyV, BKPyV and SA12, the 5′ and 3′ mature SV40 miRNAs only have 50 and 77% identity to the JCPyV and BKPyV sequences, respectively  (Figure 2A). In contrast the 3′ miRNA is 100% conserved among JCPyV, BKPyV and SA12. Consequently, in case of co-infection of e.g. JCPyV and BKPyV no differentiation of miRNA activity can be made. Remarkably, for all these miRNAs both the 5p and 3p arms are generated from the pre-miRNA hairpin and large amounts of pre-miRNA are accumulating in the cell, indicating inefficient processing of this pre-miRNA .
Up till now, limited knowledge is available on miRNAs in other polyomavirus. In murine polyomavirus (MuPyV) and Merkel Cell Virus (MCPyV), no sequence homology was found with the miRNAs identified in the alpha polyomaviruses. However, in both viruses, a miRNA was identified that is located complementary to the early mRNA transcript but located more upstream, at the 5′ end of the second LTAg exon (Figure 1B). As was the case for the alpha polyomavirus encoded miRNAs, the MuPyV miRNA was also shown to direct cleavage of the early mRNA, consequently downregulating protein expression levels of LTAg, as well as MTAg and stAg . For MCPyV targeting of the early mRNA transcripts by its miRNA was demonstrated using reporter constructs [68, 69]. Based on these observations, it appears that, despite differences in sequence or genomic location, polyomavirus miRNAs all share the property that they target the early mRNA transcript.
Recently, a miRNA has also been identified in Bandicoot Papillomatosis Carcinomatosis Virus (BPCV), a virus that shares distinct characteristics of both the Polyomaviridae and the Papillomaviridae. BPCV is a marsupial virus associated with papillomas and carcinomas in western barred bandicoots (Perameles bougainville) [70, 71]. This miRNA is not located in and complementary to the early transcript. Instead, it is located within the second non-coding region between the 3′ ends of the T-antigens and L1/L2 (Figure 1C). Furthermore, this BPCV miRNA was shown to have its own promoter located within ~60 nt of the base of the stem portion of the predicted hairpin pre-miRNA. Despite the different genomic organization, this miRNA was also shown to downregulate BPCV T-Antigens through targeting of the 3′UTR of the BPCV early transcript .
In order to get a snapshot of sequence variation in the miRNA region, an analysis was performed on a set of 643 publicly available nucleotide sequences of JCPyV isolates (Figure 2B). Besides some minor variants that only were observed very rarely, 3 variants were identified that appeared to be widespread. Two of these polymorphisms are located in the loop region between the 5′ and 3′ miRNAs and one is located in the 5′ miRNA. Of particular interest is the polymorphism in the 5′ miRNA as this appears to represent one of the 3 differences between the 5′ miRNAs of JCPyV and BKPyV, indicating that these miRNAs are even more similar than originally being described . Whether these polymorphisms impact the stability of the pre-miRNA or the functionality of the mature miRNAs needs to be investigated. For SV40, a recent study has demonstrated that different miRNA variants exist that have different host target repertoires, while their autoregulatory activity on virus-encoded early gene products is preserved .
Time-course expression analysis of the polyomavirus miRNAs all show miRNA expression late in infection [63, 64, 67]. Together with the fact that the miRNAs are encoded on the late strand, it was suggested that the pre-miRNA emanates from the viral late pre-mRNA [58, 64]. Conversely, the late polyadenylation site of polyomaviruses is located between the 3′ ends of VP1 and LTAg, suggesting that the more downstream encoded miRNA is not transcribed on the late mRNA transcript. It was however shown that the late polyadenylation site exerts only very weak polyadenylation efficiency specifically at late times in infection, thereby allowing long primary transcripts to be produced [74–76]. Furthermore, production of these long transcripts appears to lower the accumulation of early mRNAs . Whether polyomavirus miRNA expression is dependent on this late-strand read-through or whether it is produced from a so far unknown independent transcript, remains to be determined.
Autoregulatory role of Polyomavirus miRNAs
The fact that different polyomaviruses encode miRNAs that may differ in sequence and their genomic location, but all target their respective early mRNA transcript indicates an important role of these small regulatory RNA fragments in the life cycle and possibly also host interaction of this virus family. It was shown that expression of the miRNAs reduces expression of LTAg [63, 64, 67, 69]. As LTAg plays an important role in recognition of infected cells by the cytotoxic T lymphocytes (CTL), it was originally thought that miRNA mediated downregulation of the LTAg mainly plays a role in lowering recognition by the immune system . However, no differences in infection could be observed in specifically designed SV40 or MuPyV miRNA mutants, consequently questioning the importance of these miRNAs [64, 67]. Recently, however, the importance of miRNA mediated downregulation of LTAg was re-established as it was shown that downregulation of BKPyV LTAg by its own miRNA is one of the main factors controlling viral replication . Reduction of the miRNA expression level through rearrangements in the NCCR was shown to increase viral replication and as such expression of the viral miRNA might be a crucial element in establishing or maintaining viral latency or persistence . This high degree of regulation is rather atypical for miRNAs as they usually exert a more fine-tuning role. This might be attributed to the fact that these miRNAs have full complementarity to their target, thereby promoting degradation of the mRNA strand, rather than the more common translational inhibition upon imperfect complementarity. It will be interesting to see whether this essential role of the viral miRNA in controlling the viral replication is a common theme among all polyomaviruses.
Regulation of host factors by Polyomavirus miRNAs
Polyomaviruses influence host miRNAs
One of the mechanisms viruses use to disturb the physiological functions of host cells is by altering the levels of host miRNAs. Since miRNAs have been shown to function as oncogenes or tumor suppressors, this mechanism might be of particular interest for tumor-inducing polyomaviruses, such as SV40 and MCPyV . Indeed, it was shown that expression of SV40 stAg results in an induction of the human hsa-miR-27a in a PP2A dependent way, with hsa-miR-27a being a potent tumor promoter involved in cell proliferation . Similar examples of virally controlled host miRNA expression exists for the human papillomavirus HPV-31 where the virus appeared to downregulate the expression of hsa-miR-145, which in turn results in increased viral genome amplification . A more general control of host miRNA expression by polyomavirus LTAg might also not be excluded as this viral protein is known to affect RNA polymerase II-dependent transcription, which is required for production of pri-miRNAs [48, 90]. It will be of particular interest to see whether miRNA profiling studies where infected and non-infected cells are compared, reveal new host miRNAs affected by a specific polyomavirus. Similar studies with other viruses have demonstrated that this might be a successful approach to identify new host miRNAs involved in viral infection [91–94].
Host miRNAs influence polyomaviruses
Although still a rather unexplored domain in the polyomavirus field, work on other viruses has shown that not only the virus autoregulates viral mRNAs or regulates cellular mRNAs or miRNAs, but that also host miRNAs play an important role in the regulation of the expression of specific viral gene products (Figure 3). This might also play a role during viral latency or tumorigenesis. One mechanism the host might employ is the expression of functional orthologs of the viral miRNA. For SV40 it was shown that hsa-miR-423-5p may act as a functional ortholog of SV40-miR-S1-5p, which shares identical seed sequence . Together with the fact that the viral miRNA downregulates LTAg, this would then imply that hsa-miR-423-5p negatively regulates this antigenic protein, thereby reducing immune response against the virus and limiting the viral replication rate . Whereas SV40 is the only polyomavirus so far for which this has been demonstrated, the existence of these functional orthologs has also been described for the Human Immunodeficiency Virus-1 (HIV-1) , the Herpesviruses Kaposi’s sarcoma-associated herpesvirus and Marek’s Disease Virus [95–98], and Epstein-Barr virus . Although the existence of these functional orthologs appears to be a more general phenomenon, it is not clear whether these host miRNAs really evolved as a mechanism to combat specific viral infections or whether the virus – which likely evolves faster – in fact evolved to mimic specific host miRNAs.
Although the host can affect the viral life cycle through miRNAs that mimic the viral miRNAs, the host cell might also express miRNAs that specifically recognize sequences in the viral genome. This mechanism is of particular interest for disease related viruses as this cellular miRNA might be a promising drug target. The latter has been demonstrated already for hsa-miR-122 in the context of Hepatitis C Virus (HCV) infection [100, 101]. This host miRNA is highly abundant in the liver and appears to bind specific sites in the HCV genome, thereby protecting it from nucleolytic degradation . Administration of locked nucleic acid-modified antisense oligonucleotides resulted in effective viral suppression in vivo[100, 103]. So far, no miRNAs have been identified that target specific polyomavirus sequences.
Recent work has also identified hsa-miR-155 as an important host cell miRNA involved in a more general role in the immune response upon viral infection. Two reports have shown independently that this miRNA is essential for CD8+ T cell responses upon infection with lymphocytic choriomeningitis virus (LCMV), where it appeared to influence T cell survival upon viral infection [104, 105]. Whether hsa-miR-155 also plays a role in the immune control of polyomaviruses and more specifically in polyomavirus-induced diseases that are dependent on changes in the host immune system is of particular interest but remains to be determined.
Although miRNAs have only been discovered 20 years ago, they have been recognized as important regulators of several cellular processes. We have provided an overview of what is known so far on the role miRNAs play in the biology of polyomaviruses. Virally encoded miRNAs have been described in several polyomavirus and despite the fact that different locations on the genome have been discovered, they all appear to target the early mRNA transcript encoding the T-antigens. This conserved functionality already indicated an important role for these miRNAs but only recently it was discovered how this relates to control of viral replication. Next to this autoregulatory role, the polyomavirus miRNAs have been shown to target host factors as well, thereby possibly modulating the host response. It will be interesting for future work to better characterize these regulatory mechanisms, also in other polyomaviruses, as well as to study the role these play in polyomavirus related diseases. The role of host miRNAs in polyomavirus infection has only been studied to a very small extent so far. As was already the case for other viruses, it is likely that potential antiviral drug targets can be found among miRNAs, emphasizing the therapeutic potential of anti-miRs in polyomavirus related diseases. Taken together, miRNAs are shown to be essential factors in the control of polyomavirus replication and the interaction with their host. Whereas the foundation in understanding the role of miRNAs in polyomavirus biology has been laid now, this remains a rather unexplored domain with lots of potential for future research.
This work was funded by a grant from the Flemish Agency for Innovation by Science and Technology (IWT). This organization played no role in the writing of the manuscript and in the decision to submit the manuscript for publication.
- Imperiale MJ, Major EO: Polyomaviruses. In Fields Virology. 5th edition. Edited by: Knipe DM, Howley PM, Griffin DE, Lamb RA, Martin MA, Roizman B, Straus SE. Philiadelphia, PA: Lippincott Williams & Wilkins; 2007:2263–2298.
- Liddington RC, Yan Y, Moulai J, Sahli R, Benjamin TL, Harrison SC: Structure of simian virus 40 at 3.8-A resolution. Nature 1991,354(6351):278–284.PubMedView Article
- Stehle T, Gamblin SJ, Yan Y, Harrison SC: The structure of simian virus 40 refined at 3.1 A resolution. Structure 1996,4(2):165–182.PubMedView Article
- Gjoerup O, Chang Y: Update on human polyomaviruses and cancer. Adv Cancer Res 2010, 106:1–51.PubMedView Article
- International Committee on Taxonomy of Viruses., Van Regenmortel MHV, International Union of Microbiological Societies, Virology Division: Virus taxonomy: classification and nomenclature of viruses: seventh report of the International Committee on Taxonomy of Viruses. San Diego: Academic Press; 2000.
- Stewart SE, Eddy BE, Borgese N: Neoplasms in mice inoculated with a tumor agent carried in tissue culture. J Natl Cancer Inst 1958,20(6):1223–1243.PubMed
- Sweet BH, Hilleman MR: The vacuolating virus, S.V. 40. Proc Soc Exp Biol Med 1960, 105:420–427.PubMedView Article
- Gardner SD, Field AM, Coleman DV, Hulme B: New human papovavirus (B.K.) isolated from urine after renal transplantation. Lancet 1971,1(7712):1253–1257.PubMedView Article
- Padgett BL, Walker DL, ZuRhein GM, Eckroade RJ, Dessel BH: Cultivation of papova-like virus from human brain with progressive multifocal leucoencephalopathy. Lancet 1971,1(7712):1257–1260.PubMedView Article
- DeCaprio JA, Garcea RL: A cornucopia of human polyomaviruses. Nat Rev Microbiol 2013,11(4):264–276.PubMedView Article
- Dalianis T, Hirsch HH: Human polyomaviruses in disease and cancer. Virology 2013,437(2):63–72.PubMedView Article
- Van Ghelue M, Khan MT, Ehlers B, Moens U: Genome analysis of the new human polyomaviruses. Rev Med Virol 2012,22(6):354–377.PubMedView Article
- Korup S, Rietscher J, Calvignac-Spencer S, Trusch F, Hofmann J, Moens U, Sauer I, Voigt S, Schmuck R, Ehlers B: Identification of a novel human polyomavirus in organs of the gastrointestinal tract. PLoS One 2013,8(3):e58021.PubMedView Article
- Ferenczy MW, Marshall LJ, Nelson CD, Atwood WJ, Nath A, Khalili K, Major EO: Molecular biology, epidemiology, and pathogenesis of progressive multifocal leukoencephalopathy, the JC virus-induced demyelinating disease of the human brain. Clin Microbiol Rev 2012,25(3):471–506.PubMedView Article
- Tavazzi E, White MK, Khalili K: Progressive multifocal leukoencephalopathy: clinical and molecular aspects. Rev Med Virol 2011,22(1):18–32.PubMedView Article
- White MK, Khalili K: Pathogenesis of progressive multifocal leukoencephalopathy–revisited. J Infect Dis 2011,203(5):578–586.PubMedView Article
- Kuypers DR: Management of polyomavirus-associated nephropathy in renal transplant recipients. Nat Rev Nephrol 2012,8(7):390–402.PubMedView Article
- White MK, Gordon J, Khalili K: The rapidly expanding family of human polyomaviruses: recent developments in understanding their life cycle and role in human pathology. PLoS Pathog 2013,9(3):e1003206.PubMedView Article
- Jiang M, Abend JR, Johnson SF, Imperiale MJ: The role of polyomaviruses in human disease. Virology 2009,384(2):266–273.PubMedView Article
- van der Meijden E, Janssens RW, Lauber C, Bouwes Bavinck JN, Gorbalenya AE, Feltkamp MC: Discovery of a new human polyomavirus associated with trichodysplasia spinulosa in an immunocompromized patient. PLoS Pathog 2010,6(7):e1001024.PubMedView Article
- Knowles WA: Discovery and epidemiology of the human polyomaviruses BK virus (BKV) and JC virus (JCV). Adv Exp Med Biol 2006, 577:19–45.PubMedView Article
- Trowbridge PW, Frisque RJ: Identification of three new JC virus proteins generated by alternative splicing of the early viral mRNA. J Neurovirol 1995,1(2):195–206.PubMedView Article
- Abend JR, Joseph AE, Das D, Campbell-Cecen DB, Imperiale MJ: A truncated T antigen expressed from an alternatively spliced BK virus early mRNA. J Gen Virol 2009,90(Pt 5):1238–1245.PubMedView Article
- Shuda M, Feng H, Kwun HJ, Rosen ST, Gjoerup O, Moore PS, Chang Y: T antigen mutations are a human tumor-specific signature for Merkel cell polyomavirus. Proc Natl Acad Sci USA 2008,105(42):16272–16277.PubMedView Article
- Zhuang G, Wu X, Jiang Z, Kasman I, Yao J, Guan Y, Oeh J, Modrusan Z, Bais C, Sampath D, et al.: Tumour-secreted miR-9 promotes endothelial cell migration and angiogenesis by activating the JAK-STAT pathway. EMBO J 2012,31(17):3513–3523.PubMedView Article
- Lilyestrom W, Klein MG, Zhang R, Joachimiak A, Chen XS: Crystal structure of SV40 large T-antigen bound to p53: interplay between a viral oncoprotein and a cellular tumor suppressor. Genes Dev 2006,20(17):2373–2382.PubMedView Article
- Sowd GA, Fanning E: A wolf in sheep's clothing: SV40 co-opts host genome maintenance proteins to replicate viral DNA. PLoS Pathog 2012,8(11):e1002994.PubMedView Article
- Welcker M, Clurman BE: The SV40 large T antigen contains a decoy phosphodegron that mediates its interactions with Fbw7/hCdc4. J Biol Chem 2005,280(9):7654–7658.PubMedView Article
- Yardimci H, Wang X, Loveland AB, Tappin I, Rudner DZ, Hurwitz J, van Oijen AM, Walter JC: Bypass of a protein barrier by a replicative DNA helicase. Nature 2012,492(7428):205–209.PubMedView Article
- Cheng J, Rozenblatt-Rosen O, Paulson KG, Nghiem P, Decaprio JA: Merkel Cell Polyomavirus Large T Antigen has Growth Promoting and Inhibitory Activities. J Virol 2013,81(11):6118–6126.View Article
- Pallas DC, Shahrik LK, Martin BL, Jaspers S, Miller TB, Brautigan DL, Roberts TM: Polyoma small and middle T antigens and SV40 small t antigen form stable complexes with protein phosphatase 2A. Cell 1990,60(1):167–176.PubMedView Article
- Pallas DC, Weller W, Jaspers S, Miller TB, Lane WS, Roberts TM: The third subunit of protein phosphatase 2A (PP2A), a 55-kilodalton protein which is apparently substituted for by T antigens in complexes with the 36- and 63-kilodalton PP2A subunits, bears little resemblance to T antigens. J Virol 1992,66(2):886–893.PubMed
- Good PJ, Welch RC, Barkan A, Somasekhar MB, Mertz JE: Both VP2 and VP3 are synthesized from each of the alternative spliced late 19S RNA species of simian virus 40. J Virol 1988,62(3):944–953.PubMed
- Good PJ, Welch RC, Ryu WS, Mertz JE: The late spliced 19S and 16S RNAs of simian virus 40 can be synthesized from a common pool of transcripts. J Virol 1988,62(2):563–571.PubMed
- Grass DS, Manley JL: Selective translation initiation on bicistronic simian virus 40 late mRNA. J Virol 1987,61(7):2331–2335.PubMed
- Daniels R, Sadowicz D, Hebert DN: A very late viral protein triggers the lytic release of SV40. PLoS Pathog 2007,3(7):e98.PubMedView Article
- Giorda KM, Raghava S, Hebert DN: The Simian virus 40 late viral protein VP4 disrupts the nuclear envelope for viral release. J Virol 2012,86(6):3180–3192.PubMedView Article
- Khalili K, White MK, Sawa H, Nagashima K, Safak M: The agnoprotein of polyomaviruses: a multifunctional auxiliary protein. J Cell Physiol 2005,204(1):1–7.PubMedView Article
- Ng SC, Mertz JE, Sanden-Will S, Bina M: Simian virus 40 maturation in cells harboring mutants deleted in the agnogene. J Biol Chem 1985,260(2):1127–1132.PubMed
- Cheng J, DeCaprio JA, Fluck MM, Schaffhausen BS: Cellular transformation by simian virus 40 and murine polyoma virus T antigens. Semin Cancer Biol 2009,19(4):218–228.PubMedView Article
- Carter JJ, Daugherty MD, Qi X, Bheda-Malge A, Wipf GC, Robinson K, Roman A, Malik HS, Galloway DA: Identification of an overprinting gene in Merkel cell polyomavirus provides evolutionary insight into the birth of viral genes. Proc Natl Acad Sci USA 2013,110(31):12744–12749.PubMedView Article
- Lagos-Quintana M, Rauhut R, Lendeckel W, Tuschl T: Identification of novel genes coding for small expressed RNAs. Science 2001,294(5543):853–858.PubMedView Article
- Kincaid RP, Sullivan CS: Virus-encoded microRNAs: an overview and a look to the future. PLoS Pathog 2012,8(12):e1003018.PubMedView Article
- Lau NC, Lim LP, Weinstein EG, Bartel DP: An abundant class of tiny RNAs with probable regulatory roles in Caenorhabditis elegans. Science 2001,294(5543):858–862.PubMedView Article
- Lee RC, Ambros V: An extensive class of small RNAs in Caenorhabditis elegans. Science 2001,294(5543):862–864.PubMedView Article
- Bartel DP: MicroRNAs: genomics, biogenesis, mechanism, and function. Cell 2004,116(2):281–297.PubMedView Article
- Boss IW, Renne R: Viral miRNAs: tools for immune evasion. Curr Opin Microbiol 2010,13(4):540–545.PubMedView Article
- Slezak-Prochazka I, Durmus S, Kroesen BJ, van den Berg A: MicroRNAs, macrocontrol: regulation of miRNA processing. RNA 2010,16(6):1087–1095.PubMedView Article
- Bohnsack MT, Czaplinski K, Gorlich D: Exportin 5 is a RanGTP-dependent dsRNA-binding protein that mediates nuclear export of pre-miRNAs. RNA 2004,10(2):185–191.PubMedView Article
- Lund E, Guttinger S, Calado A, Dahlberg JE, Kutay U: Nuclear export of microRNA precursors. Science 2004,303(5654):95–98.PubMedView Article
- Meister G, Tuschl T: Mechanisms of gene silencing by double-stranded RNA. Nature 2004,431(7006):343–349.PubMedView Article
- Tomari Y, Zamore PD: Perspective: machines for RNAi. Genes Dev 2005,19(5):517–529.PubMedView Article
- Yigit E, Batista PJ, Bei Y, Pang KM, Chen CC, Tolia NH, Joshua-Tor L, Mitani S, Simard MJ, Mello CC: Analysis of the C. elegans Argonaute family reveals that distinct Argonautes act sequentially during RNAi. Cell 2006,127(4):747–757.PubMedView Article
- Carthew RW, Sontheimer EJ: Origins and mechanisms of miRNAs and siRNAs. Cell 2009,136(4):642–655.PubMedView Article
- Aleman LM, Doench J, Sharp PA: Comparison of siRNA-induced off-target RNA and protein effects. RNA 2007,13(3):385–395.PubMedView Article
- Djuranovic S, Nahvi A, Green R: miRNA-mediated gene silencing by translational repression followed by mRNA deadenylation and decay. Science 2012,336(6078):237–240.PubMedView Article
- Liu J, Carmell MA, Rivas FV, Marsden CG, Thomson JM, Song JJ, Hammond SM, Joshua-Tor L, Hannon GJ: Argonaute2 is the catalytic engine of mammalian RNAi. Science 2004,305(5689):1437–1441.PubMedView Article
- Sullivan CS, Ganem D: MicroRNAs and viral infection. Mol Cell 2005,20(1):3–7.PubMedView Article
- Griffiths-Jones S, Grocock RJ, Van Dongen S, Bateman A, Enright AJ: miRBase: microRNA sequences, targets and gene nomenclature. Nucleic Acids Res 2006,34(Database issue):D140-D144.PubMedView Article
- Griffiths-Jones S, Saini HK, Van Dongen S, Enright AJ: miRBase: tools for microRNA genomics. Nucleic Acids Res 2008,36(Database issue):D154-D158.PubMed
- Pfeffer S, Zavolan M, Grasser FA, Chien M, Russo JJ, Ju J, John B, Enright AJ, Marks D, Sander C, et al.: Identification of virus-encoded microRNAs. Science 2004,304(5671):734–736.PubMedView Article
- Cantalupo P, Doering A, Sullivan CS, Pal A, Peden KW, Lewis AM, Pipas JM: Complete nucleotide sequence of polyomavirus SA12. J Virol 2005,79(20):13094–13104.PubMedView Article
- Seo GJ, Fink LH, O'Hara B, Atwood WJ, Sullivan CS: Evolutionarily conserved function of a viral microRNA. J Virol 2008,82(20):9823–9828.PubMedView Article
- Sullivan CS, Grundhoff AT, Tevethia S, Pipas JM, Ganem D: SV40-encoded microRNAs regulate viral gene expression and reduce susceptibility to cytotoxic T cells. Nature 2005,435(7042):682–686.PubMedView Article
- Bauman Y, Mandelboim O: MicroRNA based immunoevasion mechanism of human polyomaviruses. RNA Biol 2011,8(4):591–594.PubMedView Article
- Bauman Y, Nachmani D, Vitenshtein A, Tsukerman P, Drayman N, Stern-Ginossar N, Lankry D, Gruda R, Mandelboim O: An identical miRNA of the human JC and BK polyoma viruses targets the stress-induced ligand ULBP3 to escape immune elimination. Cell Host Microbe 2011,9(2):93–102.PubMedView Article
- Sullivan CS, Sung CK, Pack CD, Grundhoff A, Lukacher AE, Benjamin TL, Ganem D: Murine Polyomavirus encodes a microRNA that cleaves early RNA transcripts but is not essential for experimental infection. Virology 2009,387(1):157–167.PubMedView Article
- Lee S, Paulson KG, Murchison EP, Afanasiev OK, Alkan C, Leonard JH, Byrd DR, Hannon GJ, Nghiem P: Identification and validation of a novel mature microRNA encoded by the Merkel cell polyomavirus in human Merkel cell carcinomas. J Clin Virol 2011,52(3):272–275.PubMedView Article
- Seo GJ, Chen CJ, Sullivan CS: Merkel cell polyomavirus encodes a microRNA with the ability to autoregulate viral gene expression. Virology 2009,383(2):183–187.PubMedView Article
- Bennett MD, Woolford L, Stevens H, Van Ranst M, Oldfield T, Slaven M, O'Hara AJ, Warren KS, Nicholls PK: Genomic characterization of a novel virus found in papillomatous lesions from a southern brown bandicoot (Isoodon obesulus) in Western Australia. Virology 2008,376(1):173–182.PubMedView Article
- Woolford L, Rector A, Van Ranst M, Ducki A, Bennett MD, Nicholls PK, Warren KS, Swan RA, Wilcox GE, O'Hara AJ: A novel virus detected in papillomas and carcinomas of the endangered western barred bandicoot (Perameles bougainville) exhibits genomic features of both the Papillomaviridae and Polyomaviridae. J Virol 2007,81(24):13280–13290.PubMedView Article
- Chen CJ, Kincaid RP, Seo GJ, Bennett MD, Sullivan CS: Insights into Polyomaviridae microRNA function derived from study of the bandicoot papillomatosis carcinomatosis viruses. J Virol 2011,85(9):4487–4500.PubMedView Article
- Chen CJ, Cox JE, Kincaid RP, Martinez A, Sullivan CS: Divergent microRNA Targetomes of Closely-related Circulating Strains of a Polyomavirus. J Virol 2013. in press
- Acheson NH: Efficiency of processing of viral RNA during the early and late phases of productive infection by polyoma virus. J Virol 1981,37(2):628–635.PubMed
- Hyde-DeRuyscher RP, Carmichael GG: Polyomavirus late pre-mRNA processing: DNA replication-associated changes in leader exon multiplicity suggest a role for leader-to-leader splicing in the early-late switch. J Virol 1990,64(12):5823–5832.PubMed
- Hyde-DeRuyscher R, Carmichael GG: Polyomavirus early-late switch is not regulated at the level of transcription initiation and is associated with changes in RNA processing. Proc Natl Acad Sci USA 1988,85(23):8993–8997.PubMedView Article
- Liu Z, Batt DB, Carmichael GG: Targeted nuclear antisense RNA mimics natural antisense-induced degradation of polyoma virus early RNA. Proc Natl Acad Sci USA 1994,91(10):4258–4262.PubMedView Article
- Broekema NM, Imperiale MJ: miRNA regulation of BK polyomavirus replication during early infection. Proc Natl Acad Sci USA 2013,110(20):8200–8205.PubMedView Article
- Boss IW, Renne R: Viral miRNAs and immune evasion. Biochimica et biophysica acta 2011,1809(11–12):708–714.PubMedView Article
- Raulet DH: Roles of the NKG2D immunoreceptor and its ligands. Nat Rev Immunol 2003,3(10):781–790.PubMedView Article
- Zafirova B, Wensveen FM, Gulin M, Polic B: Regulation of immune cell function and differentiation by the NKG2D receptor. CMLS 2011,68(21):3519–3529.PubMedView Article
- Raulet DH, Gasser S, Gowen BG, Deng W, Jung H: Regulation of ligands for the NKG2D activating receptor. Annu Rev Immunol 2013, 31:413–441.PubMedView Article
- Nachmani D, Stern-Ginossar N, Sarid R, Mandelboim O: Diverse herpesvirus microRNAs target the stress-induced immune ligand MICB to escape recognition by natural killer cells. Cell Host Microbe 2009,5(4):376–385.PubMedView Article
- Stern-Ginossar N, Elefant N, Zimmermann A, Wolf DG, Saleh N, Biton M, Horwitz E, Prokocimer Z, Prichard M, Hahn G, et al.: Host immune system gene targeting by a viral miRNA. Science 2007,317(5836):376–381.PubMedView Article
- You X, Zhang Z, Fan J, Cui Z, Zhang XE: Functionally orthologous viral and cellular microRNAs studied by a novel dual-fluorescent reporter system. PLoS One 2012,7(4):e36157.PubMedView Article
- Westerlaken JH, Van der Zee CE, Peters W, Wieringa B: The DMWD protein from the myotonic dystrophy (DM1) gene region is developmentally regulated and is present most prominently in synapse-dense brain areas. Brain Res 2003,971(1):116–127.PubMedView Article
- Ambros V: The functions of animal microRNAs. Nature 2004,431(7006):350–355.PubMedView Article
- Wang Q, Li DC, Li ZF, Liu CX, Xiao YM, Zhang B, Li XD, Zhao J, Chen LP, Xing XM, et al.: Upregulation of miR-27a contributes to the malignant transformation of human bronchial epithelial cells induced by SV40 small T antigen. Oncogene 2011,30(36):3875–3886.PubMedView Article
- Gunasekharan V, Laimins LA: Human papillomaviruses modulate MicroRNA 145 expression to directly control genome amplification. J Virol 2013,87(10):6037–6043.PubMedView Article
- Johnston SD, Yu XM, Mertz JE: The major transcriptional transactivation domain of simian virus 40 large T antigen associates nonconcurrently with multiple components of the transcriptional preinitiation complex. J Virol 1996,70(2):1191–1202.PubMed
- Buggele WA, Horvath CM: MicroRNA profiling of Sendai virus-infected A549 cells identifies miR-203 as an interferon-inducible regulator of IFIT1/ISG56. J Virol 2013,87(16):9260–9270.PubMedView Article
- Buggele WA, Johnson KE, Horvath CM: Influenza A virus infection of human respiratory cells induces primary microRNA expression. J Biol Chem 2012,287(37):31027–31040.PubMedView Article
- Zhang X, Daucher M, Armistead D, Russell R, Kottilil S: MicroRNA expression profiling in HCV-infected human hepatoma cells identifies potential anti-viral targets induced by interferon-alpha. PLoS One 2013,8(2):e55733.PubMedView Article
- Qi Y, Li Y, Zhang L, Huang J: microRNA expression profiling and bioinformatic analysis of dengue virusinfected peripheral blood mononuclear cells. Mol Med Rep 2013,7(3):791–798.PubMed
- Gottwein E, Mukherjee N, Sachse C, Frenzel C, Majoros WH, Chi JT, Braich R, Manoharan M, Soutschek J, Ohler U, et al.: A viral microRNA functions as an orthologue of cellular miR-155. Nature 2007,450(7172):1096–1099.PubMedView Article
- Muylkens B, Coupeau D, Dambrine G, Trapp S, Rasschaert D: Marek's disease virus microRNA designated Mdv1-pre-miR-M4 targets both cellular and viral genes. Arch Virol 2010,155(11):1823–1837.PubMedView Article
- Skalsky RL, Samols MA, Plaisance KB, Boss IW, Riva A, Lopez MC, Baker HV, Renne R: Kaposi's sarcoma-associated herpesvirus encodes an ortholog of miR-155. J Virol 2007,81(23):12836–12845.PubMedView Article
- Zhao Y, Yao Y, Xu H, Lambeth L, Smith LP, Kgosana L, Wang X, Nair V: A functional MicroRNA-155 ortholog encoded by the oncogenic Marek's disease virus. J Virol 2009,83(1):489–492.PubMedView Article
- Babu SG, Ponia SS, Kumar D, Saxena S: Cellular oncomiR orthologue in EBV oncogenesis. Comput Biol Med 2011,41(10):891–898.PubMedView Article
- Janssen HL, Reesink HW, Lawitz EJ, Zeuzem S, Rodriguez-Torres M, Patel K, van der Meer AJ, Patick AK, Chen A, Zhou Y, et al.: Treatment of HCV infection by targeting microRNA. N Engl J Med 2013,368(18):1685–1694.PubMedView Article
- Moens U: Silencing viral microRNA as a novel antiviral therapy? J Biomed Biotechnol 2009, 2009:419539.PubMedView Article
- Shimakami T, Yamane D, Jangra RK, Kempf BJ, Spaniel C, Barton DJ, Lemon SM: Stabilization of hepatitis C virus RNA by an Ago2-miR-122 complex. Proc Natl Acad Sci USA 2012,109(3):941–946.PubMedView Article
- Lanford RE, Hildebrandt-Eriksen ES, Petri A, Persson R, Lindow M, Munk ME, Kauppinen S, Orum H: Therapeutic silencing of microRNA-122 in primates with chronic hepatitis C virus infection. Science 2010,327(5962):198–201.PubMedView Article
- Dudda JC, Salaun B, Ji Y, Palmer DC, Monnot GC, Merck E, Boudousquie C, Utzschneider DT, Escobar TM, Perret R, et al.: MicroRNA-155 is required for effector CD8(+) T cell responses to virus infection and cancer. Immunity 2013,38(4):742–753.PubMedView Article
- Lind EF, Elford AR, Ohashi PS: Micro-RNA 155 is required for optimal CD8+ T cell responses to acute viral and intracellular bacterial challenges. J Immunol 2013,190(3):1210–1216.PubMedView Article
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.