Title |
Identification of Porcine Endogenous Retrovirus (PERV) packaging sequence and development of PERV packaging viral vector system |
Author |
Jiwon Choi1, Hoon-mi Kim1, Jong Kwang Yoon1, Yeondong Cho1, Hee-Jung Lee1, Kang Chang Kim1, Chang-Kyu Kim2, Gye-Woong Kim3, and Young Bong Kim1* |
Address |
1Department of Bioindustrial Technologies, Konkuk University, Seoul 143-701, Republic of Korea, 2Division of Animal Resources and Life Science, Sangji University, Wonju 220-702, Republic of Korea, 3Department of Animal Resources Community, KongJu National University, Kong-ju 314-701, Republic of Korea |
Bibliography |
Journal of Microbiology, 53(5),348-353, 2015,
|
DOI |
10.1007/s12275-015-5134-0
|
Key Words |
Porcine endogenous retrovirus, packaging signal, viral vector |
Abstract |
Studies of the retroviruses have focused on the specific interaction
of the nucleocapsid protein with a packaging signal
in the viral RNA as important for this selectivity, but the
packaging signal in porcine endogenous retrovirus (PERV)
has not been defined. Herein, we identified and analyzed
this packaging signal in PERV and found hairpin structures
with conserved tetranucleotides in their loops and nucleocapsid
recognition sequences; both of which are key elements
in the viral packaging signal of MLV. We evaluated packaging
efficiency of sequence variants isolated from viral and
proviral integrated genomes. All viral packaging sequences
(Ψ) were identical, while five distinct packaging sequences
were identified from proviral sources. One proviral sequence
(Ψ1) was identical to that of the viral Ψ and had the highest
packaging efficiency. Three variants (Ψ2, Ψ3, Ψ4) maintained
key elements of the viral packaging signal, but had nucleotide
replacements and consequently demonstrated reduced
packaging efficiency. Despite of the same overall hairpin
structure, the proviral variant (Ψ5) had only one GACG sequence
in the hairpin loop and showed the lowest packaging
efficiency other than ΔΨ, in which the essential packaging
sequence was removed. This result, thus, defined the
packaging sequences in PERV and emphasized the importance
of nucleotide sequence and RNA structure in the determination
of packaging efficiency. In addition, we demonstrate
efficient infection and gene expression from the PERVbased
viral vector, which may serve as a novel alternative to
current retroviral expression systems. |