title: Stability of a long noncoding viral RNA depends on a 9-nt core element at the RNA 5' end to interact with viral ORF57 and cellular PABPC1.
abstract: Kaposi sarcoma-associated herpesvirus (KSHV) ORF57, also known as Mta (mRNA transcript accumulation), enhances viral intron-less transcript accumulation and promotes splicing of intron-containing viral RNA transcripts. In this study, we identified KSHV PAN, a long non-coding polyadenylated nuclear RNA as a main target of ORF57 by a genome-wide CLIP (cross-linking and immunoprecipitation) approach. KSHV genome lacking ORF57 expresses only a minimal amount of PAN. In cotransfection experiments, ORF57 alone increased PAN expression by 20-30-fold when compared to vector control. This accumulation function of ORF57 was dependent on a structured RNA element in the 5' PAN, named MRE (Mta responsive element), but not much so on an ENE (expression and nuclear retention element) in the 3' PAN previously reported by other studies. We showed that the major function of the 5' PAN MRE is increasing the RNA half-life of PAN in the presence of ORF57. Further mutational analyses revealed a core motif consisting of 9 nucleotides in the MRE-II , which is responsible for ORF57 interaction and function. The 9-nt core in the MRE-II also binds cellular PABPC1, but not the E1B-AP5 which binds another region of the MRE-II. In addition, we found that PAN RNA is partially exportable in the presence of ORF57. Together, our data provide compelling evidence as to how ORF57 functions to accumulate a non-coding viral RNA in the course of virus lytic infection.
authors: Tumor Virus RNA Biology Laboratory, HIV and AIDS Malignancy Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-1868, USA.
authors: Maria J
authors: MJ
authors: Massimelli
authors: Jeong-Gu
authors: JG
authors: Kang
authors: Vladimir
authors: V
authors: Majerciak
authors: Shu-Yun
authors: SY
authors: Le
authors: David J
authors: DJ
authors: Liewehr
authors: Seth M
authors: SM
authors: Steinberg
authors: Zhi-Ming
authors: ZM
authors: Zheng
mesh_terms: D015152:Blotting, Northern; D015153:Blotting, Western; D004252:DNA Mutational Analysis; D005822:Genetic Vectors / Q000235:genetics; D057809:HEK293 Cells; D006367:HeLa Cells; D019288:Herpesvirus 8, Human / Q000235:genetics*; D006801:Humans; D047468:Immunoprecipitation; D008156:Luciferases; D009711:Nucleotides / Q000378:metabolism*; D009841:Oligonucleotides / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics / Q000502:physiology*; D039122:Poly(A)-Binding Protein I / Q000235:genetics / Q000378:metabolism*; D020871:RNA Stability / Q000235:genetics* / Q000502:physiology; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D009711:Nucleotides; D009841:Oligonucleotides; D039122:Poly(A)-Binding Protein I; D022661:RNA, Untranslated; D012367:RNA, Viral; D008156:Luciferases