Identification of a polyomavirus microRNA highly expressed in tumors

Abstract

Polyomaviruses (PyVs) are associated with tumors including Merkel cell carcinoma (MCC). Several PyVs encode microRNAs (miRNAs) but to date no abundant PyV miRNAs have been reported in tumors. To better understand the function of the Merkel cell PyV (MCPyV) miRNA, we examined phylogenetically-related viruses for miRNA expression. We show that two primate PyVs and the more distantly-related raccoon PyV (RacPyV) encode miRNAs that share genomic position and partial sequence identity with MCPyV miRNAs. Unlike MCPyV miRNA in MCC, RacPyV miRNA is highly abundant in raccoon tumors. RacPyV miRNA negatively regulates reporters of early viral (T antigen) transcripts, yet robust viral miRNA expression is tolerated in tumors. We also identify raccoon miRNAs expressed in RacPyV-associated neuroglial brain tumors, including several likely oncogenic miRNAs (oncomiRs). This work describes the first PyV miRNA abundantly expressed in tumors and is consistent with a possible role for both host and viral miRNAs in RacPyV-associated tumors.

Significance, cytomorphology of decoy cells in polyomavirus-associated nephropathy: Review of clinical, histopathological, and virological correlates with commentary

“…[45][46][47][48][49][50][51][52][53][54][55][56] Therefore, the decoy cell cytomorphologic template may be relevant for both BK and JC polyomavirocytes arising from any locus throughout the urinary tract. Unlike surgical biopsy, voided urine cytopathology may sample the entire urinary tract and because of this expanded degree of representation may prove sensitive in revealing PyV involvement through the detection of urinary decoy cells.…”

First Report of Three Major Oncogenic Viruses: Human Papillomavirus, Epstein-Barr Virus And Merkel Cell Polyomavirus in Penile Cancer

“…Mittledorf and colleagues (2012) [17] reported HPV6 and MCPyV DNA in a combined MCCinvasive SCC. Furthermore, two recent studies have already demonstrated MCPyV DNA in 19 to 37% cervical carcinomas, and one study reported a combined MCC-SCC involving HPV-MCPyV detection in the vulva [18] suggesting that MCPyV might play a role as cofactor to HPV-related cancers [7,8].…”

Identification, validation, and characterization of noncanonical miRNAs

“…However, some specialized algorithms have been developed to identify specific types of ncRNAs. Perhaps the most successful examples are algorithms to identify transfer RNA (tRNA) genes [24][25][26][27][28]. Eukaryotic tRNAs, 7SL RNA, Alu SINEs, adenovirus VA RNAs, and the murine gammaherpesvirus 68 microRNAs (miRNAs) all share a similar RNA Polymerase III (RNAP III) type 2 gene structure.…”

“…If abundant RNA from infected cells/tissues is not available, the predicted gene (the RNAP III transcription elements/predicted RNA product plus flanking sequence) can be synthesized commercially and cloned into plasmid expression vectors [19,21,26]. These vectors are then transfected into HEK293T cells and analyzed via sequencing [19,21,27] and/or Northern blot as previously described in detail [28], to determine if the DNA of interest expresses a small RNA. Next generation sequencing (currently we use the Illumina platform) of small RNAs should reveal reads consistent with a specifically processed (well-defined 5' and 3' termini) abundant small RNA, the miRNA, and typically a less abundant miRNA mapping to the other arm of the pre-miRNA hairpin.…”

“…Generally, miRNAs must be abundant enough (>100 copies per cell) to be considered bioactive [33]. This can be estimated by small RNA sequencing [19,21,27] or northern blot analysis [28] …”