Thanks again for your insights. I have still never seen a paper that uses CAV from the paw in the DRG. I thought about it, but given how CAV is not super accessible, I didn’t pursue more. Maybe it will work. Anyone know? @esypek?
Retrograde labeling with virus definitely depends on the cell types and regions. I think a lot of people are satisfied with retro-AAV in many parts of the CNS, but not all. For the DRG, there still isn’t a good solution. I’ve tried HSV from MIT and I wasn’t super impressed.
I think the Janelia folks may do a second version of retro-AAV, and they will consider peripheral neurons. AAV is definitely the friendliest and most widely used viral vector now, and having a good one for the periphery would be huge.
Lastly on a selfish note, did you inject into the skin of the paw or into the underlying muscle? What volume of virus and age of animal did you use to obtain this picture? A long time ago we were contemplating comparison of different afferent populations using viral tracing but we did not have the transgenic mouse tools at the time so it dropped off our radar. Maybe it’s time to revisit…
I injected into the skin. I’ve thought about labeling different afferents based on location, which is why I’ve been messing around with different viruses. I suspect muscle afferents would be labeled too. You would also get motor neurons though, but that likely won’t matter if you’re just trying to label.