We began distributing ready-to-use virus preps through our viral service in late 2016 and requests are still pouring in! While our lentiviral service is going strong, the AAV service has shown incredible growth this year. pAAV-hSyn-DIO-hM4D(Gi)-mCherry was the top requested AAV prep for the 2nd year running, and you can learn more about this useful, DREADD-containing AAV here. But the top requested AAV that became available in 2017 is pmSyn1-EBFP-Cre from Hongkui Zeng’s lab. This AAV has had over 150 orders since coming online!
Available in serotypes AAV1, AAV5, and AAV retrograde (the most popular form), this viral vector is used to deliver DNA encoding Cre recombinase under the control of the synapsin promoter. It can be used to drive Cre expression specifically in neurons.
AAV Delivered Cre - A Useful Tool for Neuroscientists
AAVs are widely used by neuroscientists because they efficiently deliver genes to various brain regions. You can partially control which cells are successfully infected by an AAV by altering your injection site and choosing a specific serotype, but occasionally you may want to further control where your gene of interest is expressed. A cell-type specific Cre can provide you with that control in a modular way.
For example, say you would like to label neurons with mCherry and you already have a transgenic mouse line that contains a Cre-dependent mCherry cassette under the control of an otherwise ubiquitous promoter. You could make an entirely new mouse line with mCherry controlled by a neuron specific promoter or you could breed your Cre-dependent mCherry line with a separate line that expresses Cre in neurons, but both of these options would be very time consuming.
Instead, a quick way to get the results you need would be to inject your Cre-dependent mCherry mouse with the pmSyn-EBFP-Cre AAV. Because Cre expression is controlled by the synapsin promoter, it and therefore mCherry will only be expressed in neurons. Indeed, this AAV provides you with a means to specifically activate expression of any Cre-dependent gene of interest in neurons. This ability to be paired with any Cre-controlled gene of interest makes pmSyn-BFP-Cre highly modular.
Further Uses of pmSyn1-EBFP-Cre
Of course there are also more complicated ways to use this particular AAV. For instance, you might use it as part of a flex switch you’d like to work with in neurons or you might use it in combination with Flp-FRT. Additionally, you could use the retrograde form to specifically express Cre in neurons with axons that extend to your injection site. This would help you map signalling between different regions of the brain. There are many possibilities enabled by this highly modular AAV - that’s probably why it’s so popular!
We’re excited to see how you continue to use pmSyn1-EBFP-Cre and other viral vector tools in the years to come. We’ll make many more viral vector tools and resources available in the coming months so be sure to check back often!
To find more viral vectors available through Addgene, be sure to check out our viral service page and browse our viral vector blog posts for many more tips and ideas on how to use these fantastic tools in your experiments.
Many thanks to Hongkui Zeng’s lab for providing this AAV vector!
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- AAV: A Versatile Tool for Gene Expression in Mammals
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