Intersectional strategies to target spinal cord projection neurons - inquiry

Experimental Techniques
1

Hello. I am trying to use intersectional strategies to target VPL Projecting neurons from the spinal cord.
My original plan was to intraspinally inject cre dependent DREADD around p15-20 and then inject AAV retro Cre in the brain around P42 to selectively express the DREADD.
However, I am concerned if the order of injection matters in this case? Would the spinal cord neurons be infected with the DREADD virus still without the CRE and get later expressed?
I have read papers that inject the two viruses at the same time in different brain regions but don’t know if having a long term between injections would change the results.

Any tips or advice would be appreciated!
Thank you

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I think your best bet is to just do a small pilot and make sure you can see your transgene. DREADDs are known to be annoying to visualize by IHC. I think there is an HA tag on it, but I’ve never really seen great IHC. You might try a Cre-dependent fluoro like Tomato or GFP in the spinal cord, and then inject your Cre in the brain. That will tell you what you need to know.

But in general, yes, I think what you’re trying to do is very achievable and the AAV in the spinal cord should be hanging around a few weeks later. Most people wait at least 3 weeks anyway for expression to take hold, and then longer.

@SamineniV

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