Difference between revisions of "Part:BBa K404252"

ViralBrick-587KO-Empty

The primary receptor of AAV-2 is the heparan sulfate proteoglycan (HSPG) receptor (Perabo et al. 2006). Its binding motif consists of five amino-acids located on the capsid surface: R484/R487, K532, R585/587. (Trepel et al. 2009). The positively charged arginine residues interact with the HSPGs' negatively charged acid residues. Opie et al. have shown that two point mutations (R585A and R588A) are sufficient to eliminate the heparin binding affinity in AAV2. (Opie et al. 2003). This ViralBrick has been created to introduce this knockout into other constructs. The biobricks with containing this knockout are annotated with „HSPG-ko“.

[AAV2]-VP123ex

The pSB1C3_001_CMV_VP123 contains a CMV promoter upstream the VP123 sequence. The AAV capsid consists of 60 capsid protein subunits. The three cap proteins VP1, VP2, and VP3 are encoded in an overlapping reading frame. Arranged in a stoichiometric ratio of 1:1:10, they form an icosahedral symmetry. The mRNA encoding for the cap proteins is transcribed from p40 and alternative spliced to minor and major products. Alternative splicing and translation initiation of VP2 at a nonconventional ACG initiation codon promote the expression of VP1, VP2 and VP3. The VP proteins share a common C terminus and stop codon, but begin with a different start codon. The N termini of VP1 and VP2 play important roles in infection and contain motifs that are highly homologous to the phospholipase A2 (PLA2) domain and nuclear localization signals (BR)(+).
CMV promoter is derived from human Cytomegalovirus, which belongs to Herpesvirus group. All family members share the ability to remain in latent stage in the human body. CMV is located upstream of immediate-early gene. However, CMV promoter is an example of widely used promoters and is present in mammalian expression vectors. The advantage of CMV is the high-level constitutive expression in mostly all human tissues [Fitzsimons et al., 2002].

References

DiPrimio, Asokan, Govindasamy, Agbandje-McKenna, & Samulski, June 2008. Surface loop dynamics in adeno-associated virus capsid assembly. Journal of virology, 167(1), 5178–5189
Fitzsimons, H.L., Bland, R.J. & During, M.J. 2002. Promoters and regulatory elements that improve adeno-associated virus transgene expression in the brain. Methods San Diego Calif, 28(2), pp.227-236. Available at: http://www.ncbi.nlm.nih.gov/pubmed/12413421.

Figure 1: The VP proteins are encoded in an overlapping open reading frame.