Neuron-specific and high-level transgene expression with the AAV-SynTetOff-GFP vector <i>in vivo</i>.

<p>(<b>A</b>_<b>1</b><b>–C</b>_<b>4</b>) One week after the injection of the AAV vectors, GFP-NF was observed in the caudate-putamen (CPu). Cells infected with the vector AAV2/1-SynTetOff-GFP (C) were more strongly labeled with GFP than those infected with the vectors AAV2/1-CMV-GFP-BGHpA (A) and AAV2/1-SYN-GFP-BGHpA (B). Almost all GFP-positive cells were also immunoreactive for NeuN with AAV2/1-SYN-GFP-BGHpA (B₂–B₄, arrowheads) and AAV2/1-SynTetOff-GFP (C₂–C₄, arrowheads), whereas some GFP-positive cells were negative for NeuN with the AAV2/1-CMV-GFP-BGHpA vector (A₂–A₄, arrow; a putative glial cell). Scale bar in A₁ applies to A₁–C₁; Scale bar in A₂ applies to A₂–A₄, B₂–B₄, and C₂–C₄. (<b>D</b>) Specificities of GFP expression in neostriatal neurons. AAV2/1-SYN-GFP-BGHpA and AAV2/1-SynTetOff-GFP displayed specific expression in neuronal cells, while the expression of GFP with AAV2/1-CMV-GFP-BGHpA was not neuron-specific. (<b>E</b>) GFP-NF intensities in neostriatal neurons. The mean GFP-NF intensity with AAV2/1-CMV-GFP-BGHpA was standardized as 1 AU. AAV2/1-SynTetOff-GFP transduced much stronger GFP expression in neurons than AAV2/1-CMV-GFP-BGHpA and AAV2/1-SYN-GFP-BGHpA (factors of 43.3 and 34.3, respectively). Error bars, ± SEM. *<i>p</i> < 0.05, **<i>p</i> < 0.01, ***<i>p</i> < 0.001.