DOI: 10.5061/dryad.ht76hdrr3
title: Laminar specificity and coverage of viral-mediated gene expression restricted to GABAergic interneurons and their parvalbumin subclass in marmoset primary visual cortex

description: In the mammalian neocortex, inhibition is important for dynamically
 balancing excitation and shaping the response properties of cells and
 circuits. The various computational functions of inhibition are thought to
 be mediated by different inhibitory neuron types of which a large
 diversity exists in several species. Current understanding of the function
 and connectivity of distinct inhibitory neuron types has mainly derived
 from studies in transgenic mice. However, it is unknown whether knowledge
 gained from mouse studies applies to the non-human primate, the model
 system closest to humans. The lack of viral tools to selectively access
 inhibitory neuron types has been a major impediment to studying their
 function in the primate. Here, we have thoroughly validated and
 characterized several recently-developed viral vectors designed to
 restrict transgene expression to GABAergic cells or their parvalbumin (PV)
 subtype, and identified two types that show high specificity and
 efficiency in marmoset V1. We show that in marmoset V1 AAV-h56D induces
 transgene expression in GABAergic cells with up to 91-94% specificity and
 79% efficiency, but this depends on viral serotype and cortical layer.
 AAV-PHP.eB-S5E2 induces transgene expression in PV cells across all
 cortical layers with up to 98% specificity and 86-90% efficiency,
 depending on layer. Thus, these viral vectors are promising tools for
 studying GABA and PV cell function and connectivity in the primate cortex.
description: To facilitate the application of these inhibitory-neuron specific
 viral vectors to studies of the primate cortex, we have performed a
 thorough validation and characterization of the laminar expression of
 reporter proteins mediated by several enhancer/promoter-specific AAVs.
 Here we report results from the two vector types that have shown the
 greatest specificity of transgene expression in marmoset primary visual
 cortex (V1); specifically, we have tested three serotypes of the
 <em>h56D </em>promoter-AAV that restricts gene expression to
 GABAergic neurons (Mehta et al., 2019), and one serotype of the S5E2
 enhancer-AAV that restricts gene expression to PV cells
 (Vormstein-Schneider et al., 2020). Using injections of these viral
 vectors in marmoset V1, combined with immunohistochemical identification
 of GABA and PV neurons, we find that the laminar distribution of reporter
 protein expression mediated by the GABA- and PV-enhancer AAVs validated in
 this study resembles the laminar distribution of GABA-immunoreactive
 (GABA+) and PV-immunoreactive (PV+) cells, respectively, in marmoset
 V1
description: # Laminar specificity and coverage of viral-mediated gene expression
 restricted to GABAergic interneurons and their parvalbumin subclass in
 marmoset primary visual cortex
 [https://doi.org/10.5061/dryad.ht76hdrr3](https://doi.org/10.5061/dryad.ht76hdrr3) ## Description of the data and file structure Here, we have thoroughly validated and characterized several recently-developed viral vectors designed to restrict transgene expression to GABAergic cells or their parvalbumin (PV) subtype, and identified two types that show high specificity and efficiency in marmoset primary visual cortex. **ManuscriptFig2*_*Data*_*Table_ver4**: This spreadsheet contains the values for the graphs found in Figure2.  Null values are present for the Layer 4A and 4B mouse data taken from Xu et al. 2010 as this data was not published. *MeanPV% - Normalized percentage of parvalbumin positive cells found in each cortical layer.* *MeanGABA% - Normalized percentage of GABA positive cells found in each cortical layer.* *Mean PV cell density - Mean cell density of parvalbumin positive cells found in each cortical layer.* *Mean GABA cell density - Mean cell density of GABA positive cells found in each cortical layer.* *PV Mouse V1 Xu 2010 - Mean cell density of parvalbumin positive cells found in each cortical layer of the mouse as reported in Xu et al 2010.* *GABA Mouse V1 Xu 2010 - Mean cell density of GABA positive cells found in each cortical layer of the mouse as reported in Xu et al 2010.* *PV cells % GABA positive - Percent of parvalbumin positive cells that were also GABA positive.* *GABA cells % PV positive - Percent of GABA positive cells that were also parvalbumin positive.* **ManuscriptFig4*_*Data*_*Table_ver5**: This spreadsheet contains the values for the graphs found in Figure4. The 3 null values in the Specificity data are due to low n's.  The Standard Error of the Mean could not be computed for these cells. *% GABA IHC* - *Normalized percentage of GABA positive cells found in each cortical layer as determined by immunohistochemistry.* *% AAV9* - *Normalized percentage of AAV9 viral infected cells found in each cortical layer (Fig 4A) as well as the specificity (Fig4B) and coverage (Fig4C) of AAV9 virally labeled cells.* *% AAV7* - *Normalized percentage of AAV7 viral infected cells found in each cortical layer (Fig 4A) as well as the specificity (Fig4B) and coverage (Fig4C) of AAV7 virally labeled cells.* *% AAV1* - *Normalized percentage of AAV1 viral infected cells found in each cortical layer (Fig 4A) as well as the specificity (Fig4B) and coverage (Fig4C) of AAV1 virally labeled cells.* **ManuscriptFig6*_*Data*_*Table_ver3**: This spreadsheet contains the values for the graphs found in Figure6. The null value in the Specificity data are due to low n.  The Standard Error of the Mean could not be computed for this cell. *% PV IHC* - *Normalized percentage of PV positive cells found in each cortical layer immunohistochemistry.* *% Small Volume Injection* - *Normalized percentage of AAV viral infected cells found in each cortical layer (Fig 4A) as well as the specificity (Fig4B) and coverage (Fig4C) of virally labeled cells after small volume 100nL injections.* *% Mid Volume Injection* - *Normalized percentage of AAV viral infected cells found in each cortical layer (Fig 4A) as well as the specificity (Fig4B) and coverage (Fig4C) of AAV virally labeled cells after mid volume 180nL injections.* *% Large Volume Injection* - *Normalized percentage of AAV1 viral infected cells found in each cortical layer (Fig 4A) as well as the specificity (Fig4B) and coverage (Fig4C) of AAV1 virally labeled cells after mid volume 180nL injections* ## Code/software Microsoft Excel