Retroviral psi packaging element

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Retroviral Psi packaging element
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Human immunodeficiency virus type 1 dimerisation initiation site
sequence conservation of HIV-1_DIS
Identifiers
SymbolHIV-1_DIS
Alt. SymbolsRetroviral_psi
RfamRF00175
Other data
RNA typeCis-regp
Domain(s)Viruses
SOSO:0000233
PDB structuresPDBe

The retroviral psi packaging element, also known as the Ψ RNA packaging signal, is a

unspliced
copies of the viral genome.

A 3D representation that includes the retroviral psi packaging element. This is a solution RNA structure model of the HIV-1 dimerization initiation site in the kissing-loop dimer.[7]

In HIV, the psi element is around 80–150

initiation codon.[8] It has a known secondary structure composed of four hairpins called SL1 to SL4 (SL is for Stem-loop) which are connected by relatively short linkers. All four stem loops are important for genome packaging and each of the stem loops SL1,[8] SL2,[9] SL3 [10][11] and SL4 [12]
has been independently expressed and structurally characterised.

Stem loop 1 (SL1) (also referred to as HIV-1_DIS) consists of a

conserved hairpin structure with a palindromic loop sequence which was predicted and confirmed by mutagenesis.[13] This palindromic loop is known as the primary dimer initiation site (DIS) as it is believed to promote dimerization of the viral genome through formation of a "kissing dimer" intermediate.[14] The Rfam
structure shown is based on a covariation model.

It has been shown that SL1 may provide a secondary binding site for the viral Rev protein.[15] The Rev protein is an essential HIV regulatory protein which increases the stability and transport of the unspliced viral RNA.[16]

Stem-loop 2 (SL2) (also referred to as HIV-1 SD) consists of a highly conserved 19 nt stem-loop which has been shown by mutagenesis to modulate the splicing efficiency of HIV-1 mRNAs.[17]

Stem-loop 3 (SL3) consists of a highly conserved 14 nt stem-loop which was predicted and confirmed by mutagenesis and mass spectrometric detection (MS3D). HIV-1 SL3 is sufficient by itself to induce heterologous RNA into virus-like particles but its deletion does not eliminate encapsidation.[17]

Stem-loop 4 (SL4) consists of a highly conserved 14 nt stem-loop that is located just downstream of the gag start codon. The structure was confirmed by

NMR and mass spectrometric detection (MS3D).[17] It also may have coding and non-coding
roles.

References

  1. PMID 2760989
    .
  2. PMID 12917463
    .
  3. PMID 9032337
    .
  4. PMID 9151848
    .
  5. PMID 8627772
    .
  6. PMID 17586311
    .
  7. PMID 16272570
    .
  8. ^
    PMID 12559920
    .
  9. PMID 10926523
    .
  10. PMID 10736224
    .
  11. PMID 9743628
    .
  12. PMID 11724565
    .
  13. PMID 8794309
    .
  14. PMID 8197162
    .
  15. PMID 12851400
    .
  16. PMID 2784208
    .
  17. ^
    PMID 18160437
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Retroviral_psi_packaging_element&oldid=1192726374"