title: Kaposi's sarcoma-associated herpesvirus microRNA single-nucleotide polymorphisms identified in clinical samples can affect microRNA processing, level of expression, and silencing activity.
abstract: Kaposi's sarcoma-associated herpesvirus (KSHV) encodes 12 pre-microRNAs that can produce 25 KSHV mature microRNAs. We previously reported single-nucleotide polymorphisms (SNPs) in KSHV-encoded pre-microRNA and mature microRNA sequences from clinical samples (V. Marshall et al., J. Infect. Dis., 195:645-659, 2007). To determine whether microRNA SNPs affect pre-microRNA processing and, ultimately, mature microRNA expression levels, we performed a detailed comparative analysis of (i) mature microRNA expression levels, (ii) in vitro Drosha/Dicer processing, and (iii) RNA-induced silencing complex-dependent targeting of wild-type (wt) and variant microRNA genes. Expression of pairs of wt and variant pre-microRNAs from retroviral vectors and measurement of KSHV mature microRNA expression by real-time reverse transcription-PCR (RT-PCR) revealed differential expression levels that correlated with the presence of specific sequence polymorphisms. Measurement of KSHV mature microRNA expression in a panel of primary effusion lymphoma cell lines by real-time RT-PCR recapitulated some observed expression differences but suggested a more complex relationship between sequence differences and expression of mature microRNA. Furthermore, in vitro maturation assays demonstrated significant SNP-associated changes in Drosha/DGCR8 and/or Dicer processing. These data demonstrate that SNPs within KSHV-encoded pre-microRNAs are associated with differential microRNA expression levels. Given the multiple reports on the involvement of microRNAs in cancer, the biological significance of these phenotypic and genotypic variants merits further studies in patients with KSHV-associated malignancies.
authors.affiliation: Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA.
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Han
authors.forename: Vickie
authors.initials: V
authors.lastname: Marshall
authors.forename: Eugene
authors.initials: E
authors.lastname: Barsov
authors.forename: Octavio
authors.initials: O
authors.lastname: Quiñones
authors.forename: Alex
authors.initials: A
authors.lastname: Ray
authors.forename: Nazzarena
authors.initials: N
authors.lastname: Labo
authors.forename: Matthew
authors.initials: M
authors.lastname: Trivett
authors.forename: David
authors.initials: D
authors.lastname: Ott
authors.forename: Rolf
authors.initials: R
authors.lastname: Renne
authors.forename: Denise
authors.initials: D
authors.lastname: Whitby
mesh_terms: D002478:Cells, Cultured; D015967:Gene Expression Regulation, Viral; D057809:HEK293 Cells; D006566:Herpesviridae Infections / Q000235:genetics* / Q000821:virology; D019288:Herpesvirus 8, Human / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D008156:Luciferases / Q000378:metabolism; D054685:Lymphoma, Primary Effusion / Q000235:genetics / Q000821:virology*; D035683:MicroRNAs / Q000235:genetics* / Q000502:physiology; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012323:RNA Processing, Post-Transcriptional / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D035683:MicroRNAs; D012333:RNA, Messenger; D012367:RNA, Viral; D008156:Luciferases