Fig. 1

Virally mediated peptide delivery and expression system. A: Schematic diagram of recombinant lentiviral vectors. Control, a lentiviral vector expressing GFP; Peptide, lentiviral vector expressing peptide artificial precursor and GFP. LTR: long terminal repeat; Ψ: a packaging sequence; RRE: rev response element; cPPT: a central polypurin track sequence; IRES: internal ribosomal entry site; WPRE: a woodchuck hepatitis virus posttranscriptional regulatory element. Peptide precursor composed of the proNGF/proBDNF domain fused to TAT domain, HA tag, and peptide sequence of interest. B: proBDNF/NGF mRNA is translated into proBDNF/NGF protein in the endoplasmic reticulum. Pre-proBDNF/NGF is then transported into the golgi apparatus and processed to the mature form of BDNF/NGF (mBDNF/mNGF) by extracellular protein convertase 1 (PC1) within the vesicles. The secretory granules are trafficked to the sites of release in the axonal or dendritic terminals. Neurons secrete both proBDNF/NGF and mBDNF/mNGF in an activity-dependent manner (BDNF) of continuously (NGF). The tissue-type plasminogen activator (tPA) activates a plasminogen, which then cleaves the precursor molecule. Alternatively, extracellular metalloproteinases (MMP) process proBDNF/NGF to generate mBDNF/mNGF (Reviewed by Marosi & Mattson, 2014). C: proBDNF/proNGF-EPE or GFP LVs transduced COS7 cells were grown on PLL coated cover slips in a 12 well plate to 50% confluence. On the day of the experiment, cells were fixed with paraformaldehyde (PFA) 4%, and immunostained using anti Ha-Tag 1:200 (red), nuclei were stained by DAPI 1:5000 (blue), and viral transduction was detected by GFP fluorescence (green)