"D" matters in recombinant AAV DNA packaging.
"D" matters in recombinant AAV DNA packaging.
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“D”在重组 AAV DNA 包装中很重要。
DOI：
10.1016/j.ymthe.2021.05.002
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Xiao,Weidong
中科院分区：
文献类型：
--
作者：
Zhang,Junping;Guo,Ping;Xu,Yinxia;Mulcrone,PatrickL;Samulski,RJude;Xiao,Weidong
Unmethylated CpG dinucleotide-based motifs (CpGs) have been documented as pathogen-associated molecular patterns (PAMPs) that bind to Toll-like receptor (TLR) 9 pattern recognition receptors and lead to adaptive effector functions that result in a loss of transduced cells. 1 Vector genome hypomethylation has been recognized as a deficiency of current methods of generation of adeno-associated viral (AAV) vectors. 2 Although wild-type parvovirus DNA has been shown to be generally hypomethylated 3 in its replication cycle, one additional source of hypomethylation in recombinant AAV (rAAV) genomes stems from the encapsidation of unreplicated vector genomes, which are often directly derived from bacterial plasmid DNA origin. 2 Since the mainstay method for clinical AAV production has been based on triple plasmid transfection, understanding the mechanism of the direct packaging of plasmid-derived DNA is necessary to find a solution to this problem.Traditionally, we think of AAV vector production as involving DNA replication. AAV vector genomes are constructed by flanking the expression cassette with two copies of AAV inverted terminal repeat (ITR) as the essential cis elements to facilitate the replication of vector DNA and packaging. 4 A key element in the AAV ITR identified to control such a function is the D-element (“D”), which is a 20-nucleotide sequence that is highly conserved among various AAV serotypes.“D” is a unique region of AAV ITR that is not part of the palindromic sequences. In addition, the “D” is located near the terminal resolution site, which is the initial site for rescue, replication, and packaging. 5–7 AAV rep genes and capsid genes along with a set of helper virus genes are provided in trans to complement the functionality of the AAV ITR and D-element during vector production.
