Investigators at Indian Institute of Science Report Findings in Capsid (Bioengineering of AAV2 Capsid at Specific Serine, Threonine, or Lysine Residues Improves Its Transduction Efficiency in Vitro and in Vivo)
By a News Reporter-Staff News Editor at Gene Therapy Weekly -- Research findings on Capsid are discussed in a new report. According to news originating from Bengaluru, India, by NewsRx correspondents, research stated, "We hypothesized that the AAV2 vector is targeted for destruction in the cytoplasm by the host cellular kinase/ubiquitination/proteasomal machinery and that modification of their targets on AAV2 capsid may improve its transduction efficiency. In vitro analysis with pharmacological inhibitors of cellular serine/threonine kinases (protein kinase A, protein kinase C, casein kinase II) showed an increase (20-90%) on AAV2-mediated gene expression."
Our news journalists obtained a quote from the research from the Indian Institute of Science, "The three-dimensional structure of AAV2 capsid was then analyzed to predict the sites of ubiquitination and phosphorylation. Three phosphodegrons, which are the phosphorylation sites recognized as degradation signals by ubiquitin ligases, were identified. Mutation targets comprising eight serine (S) or seven threonine (T) or nine lysine (K) residues were selected in and around phosphodegrons on the basis of their solvent accessibility, overlap with the receptor binding regions, overlap with interaction interfaces of capsid proteins, and their evolutionary conservation across AAV serotypes. AAV2-EGFP vectors with the wild-type (WT) capsid or mutant capsids (15 S/T ? alanine [A] or 9 K ? arginine [R] single mutant or 2 double K ? R mutants) were then evaluated in vitro. The transduction efficiencies of 11 S/T ? A and 7 K ? R vectors were significantly higher (similar to 63-90%) than the AAV2-WT vectors (similar to 30-40%). Further, hepatic gene transfer of these mutant vectors in vivo resulted in higher vector copy numbers (up to 4.9-fold) and transgene expression (up to 14-fold) than observed from the AAV2-WT vector. One of the mutant vectors, S489A, generated similar to 8-fold fewer antibodies that could be cross-neutralized by AAV2-WT."
According to the news editors, the research concluded: "This study thus demonstrates the feasibility of the use of these novel AAV2 capsid mutant vectors in hepatic gene therapy."
For more information on this research see: Bioengineering of AAV2 Capsid at Specific Serine, Threonine, or Lysine Residues Improves Its Transduction Efficiency in Vitro and in Vivo. Human Gene Therapy Methods, 2013;24(2):80-117. Human Gene Therapy Methods can be contacted at: Mary Ann Liebert, Inc, 140 Huguenot Street, 3RD Fl, New Rochelle, NY 10801, USA (see also Capsid).
The news correspondents report that additional information may be obtained from N. Gabriel, Indian Inst Sci, Mol Biophys Unit, Bengaluru 560012, India. Additional authors for this research include S. Hareendran, D. Sen, R.A. Gadkari, G. Sudha, R. Selot, M. Hussain, R. Dhaksnamoorthy, R. Samuel, N. Srinivasan, A. Srivastava and G.R. Jayandharan.
Keywords for this news article include: Asia, India, Kinase, Lysine, Serine, Virion, Bengaluru, Threonine, Nucleocapsid, Basic Amino Acids, Diamino Amino Acids, Neutral Amino Acids, Enzymes and Coenzymes, Essential Amino Acids
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