The VA (viral associated) RNA is a type of

non-coding RNA A non-coding RNA (ncRNA) is a functional RNA molecule that is not Translation (genetics), translated into a protein. The DNA sequence from which a functional non-coding RNA is transcribed is often called an RNA gene. Abundant and functionally im ...

found in

adenovirus Adenoviruses (members of the family ''Adenoviridae'') are medium-sized (90–100 nm), nonenveloped (without an outer lipid bilayer) viruses with an icosahedral nucleocapsid containing a double-stranded DNA genome. Their name derives from the ...

. It plays a role in regulating

translation Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The ...

. 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. VAII does not stimulate translation. Transient transfection assays have shown that VAI-RNA increases the stability of ribosome-bound transcripts. VAI RNA is processed in the cell to create 22 nucleotide long RNAs that can act as

siRNA Small interfering RNA (siRNA), sometimes known as short interfering RNA or silencing RNA, is a class of double-stranded RNA at first non-coding RNA molecules, typically 20-24 (normally 21) base pairs in length, similar to miRNA, and operating wi ...

miRNA MicroRNA (miRNA) are small, single-stranded, non-coding RNA molecules containing 21 to 23 nucleotides. Found in plants, animals and some viruses, miRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miRN ...

. VAI RNA functions as a decoy RNA for the double stranded RNA activated

protein kinase R Protein kinase RNA-activated also known as protein kinase R (PKR), interferon-induced, double-stranded RNA-activated protein kinase, or eukaryotic translation initiation factor 2-alpha kinase 2 (EIF2AK2) is an enzyme that in humans is encoded by t ...

which would otherwise phosphorylate eukaryotic initiation factor 2.

Structure

VA RNA is composed of two

stem-loop Stem-loop intramolecular base pairing is a pattern that can occur in single-stranded RNA. The structure is also known as a hairpin or hairpin loop. It occurs when two regions of the same strand, usually complementary in nucleotide sequence when ...

s separated by a central region essential for function.

References

External links

* Non-coding RNA {{molecular-cell-biology-stub