Increasing the number of<unk><unk> s increases the specificity by increasing the number of base pairs that the ZFN can bind to. However too many<unk><unk> s can lead to off-target binding and thus offsite cleavage. This is due to an increased likelihood of<unk><unk> s binding to parts of the genome outside of the gene of interest. Current ZFN<unk> s focus on the CCR5 gene as no known side effects result from altering CCR5. There are strains of HIV that are able to use CXCR4 to enter the host cell, bypassing CCR5 altogether. The same gene editing technology has been applied to CXCR4 alone and in combination with CCR5 Several issues exist with this experimental<unk> . One issue lies in ensuring that the desired repair mechanism is the one that is used to repair the DSB following gene addition. Another issue with the disruption of the CCR5 gene is that CXCR4-specific or dual-tropic strains are still able to access the cell. This method can prevent the progression of HIV infection. To employ the ZFNs in clinical settings the following criteria must be met: i) High specificity of DNA-binding – Correlates with better performance and less toxicity of ZFNs. Engineered ZFNs take into account positional and context-dependent effects of<unk><unk> s to increase specificity. ii) Enable allosteric activation of FokI once bound to DNA in order for it to produce only the required DSB. iii) To deliver two different<unk><unk><unk>  subunits and donor DNA to the cell, the vectors that are used need to be improved to decrease the risk of mutagenesis. These include adeno-associated virus vectors, integrase-deficient lentiviral vectors and adenovirus type 5 vectors. iv) Transient expression of ZFNs is preferred over permanent expression of these proteins to avoid ‘off-target’ effects. v) During gene targeting, genotoxicity associated with high expression of ZFNs might lead to cell apoptosis and thus needs to be thoroughly verified in vitro and in vivo transformation assays.
Zinc finger nuclease treatment of HIV
Discovery and development of non-nucleoside reverse-transcriptase inhibitors
Discovery and development of nucleoside and nucleotide reverse-transcriptase inhibitors
Innate resistance to HIV
HIV vaccine development
Cancer vaccine targeting CD4+ T cells
Zika virus vaccine
T cell receptor T cell therapy