VA RNA
{{Short description|Non-coding RNA found in adenovirus}}
{{Infobox rfam
| Name = VA RNA
| image = RF00102.jpg
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| caption = Predicted secondary structure and sequence conservation of VA
| Symbol = VA
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| Rfam = RF00102
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| RNA_type = Gene
| Tax_domain = Eukaryota; Viruses
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| SO = {{SO|0005836}}
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The VA (viral associated) RNA is a type of non-coding RNA found in adenovirus.{{cite book | last = Mathews | first = MB | chapter = Structure, Function, and Evolution of Adenovirus Virus-Associated RNAs | year = 1995 | title = The Molecular Repertoire of Adenoviruses II | journal = Curr Top Microbiol Immunol | series = Current Topics in Microbiology and Immunology | volume = 199 | pages = 173–187 | doi = 10.1007/978-3-642-79499-5_7 | pmid = 7555067| isbn = 978-3-642-79501-5 }}{{cite journal | last = Kidd | first = AH |author2=Garwicz D |author3=Oberg M | year = 1995 | title = Human and simian adenoviruses: phylogenetic inferences from analysis of VA RNA genes | journal = Virology | volume = 207 | issue = 1 | pages = 32–45 | pmid = 7871747 | doi = 10.1006/viro.1995.1049| doi-access = free }} It plays a role in regulating translation.{{cite journal | last = Thimmappaya | first = B |author2=Weinberger C |author3=Schneider RJ |author4=Shenk T | year = 1982 | title = Adenovirus VAI RNA is required for efficient translation of viral mRNAs at late times after infection | journal = Cell | volume = 31 | pages = 543–551 | pmid = 6297772 | doi = 10.1016/0092-8674(82)90310-5 | issue = 3 Pt 2| s2cid = 42720272 }} There are two copies of this RNA called VAI or VA RNAI and VAII or VA RNAII. These two VA RNA genes are distinct genes in the adenovirus genome. VA RNAI is the major species with VA RNAII expressed at a lower level. Neither transcript is polyadenylated and both are transcribed by PolIII.
Function
VAI stimulates the translation of both early and late viral genes including E3 and hexon.{{cite journal | last = Svensson | first = C |author2=Akusjarvi G | year = 1984 | title = Adenovirus VA RNAI: a positive regulator of mRNA translation | journal = Mol Cell Biol | volume = 4 | pages = 736–742 | pmid = 6201722 | issue = 4 | pmc = 368790 | doi = 10.1128/mcb.4.4.736}} VAII does not stimulate translation. Transient transfection assays have shown that VAI-RNA increases the stability of ribosome-bound transcripts.{{cite journal | last = Strijker | first = R |author2=Fritz DT |author3=Levinson AD | year = 1989 | title = Adenovirus VAI-RNA regulates gene expression by controlling stability of ribosome-bound RNAs | journal = EMBO J | volume = 8 | pages = 2669–2675 | pmid = 2583126 | issue = 9 | pmc = 401273 | doi = 10.1002/j.1460-2075.1989.tb08407.x}}
VAI RNA is processed in the cell to create 22 nucleotide long RNAs that can act as siRNA or miRNA.{{cite journal |vauthors=Sano M, Kato Y, Taira K | title = Sequence-specific interference by small RNAs derived from adenovirus VAI RNA | journal = FEBS Lett. | volume = 580 | issue = 6 | pages = 1553–1564 | year = 2006 | pmid = 16472808 | doi = 10.1016/j.febslet.2006.01.085| s2cid = 6612125 | doi-access = free }} VAI RNA functions as a decoy RNA for the double stranded RNA activated protein kinase R which would otherwise phosphorylate eukaryotic initiation factor 2.
Structure
VA RNA is composed of two stem-loops separated by a central region essential for function.{{cite journal | last = Ma | first = Y |author2=Mathews MB | year = 1996 | title = Secondary and tertiary structure in the central domain of adenovirus type 2 VA RNA I | journal = RNA | volume = 2 | pages = 937–951 | pmid = 8809020 | issue = 9 | pmc = 1369428}}
References
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