Good morning,

I am trying to find a fluorescent protein with fast expression time (ideally hours or 1 day from expression induction to maturation). I want to use TRAP2 mice (Fos-CreERT2) and viral injections of AAV-DIO-fluorescent protein to tag and detect memory-related ensemble neurons. In all papers I found with similar approaches, the authors have to wait 4 to 7 days before having detectable fluorescent protein expression, but I need much faster expression times. Out of the many causes that could account for this 4-7 days delay between behavioral experience and achieving detectable levels of fluorescent protein (activity-dependent induction of iCre expression, iCre transcription and translation, hydroxitamoxifen-mediated iCre translocation to the nucleus, iCre-mediated DNA recombination and fluorescent protein expression) I think fluorescent protein expression and maturation times may play a major role. I have seen in some papers that the authors used tdTomato as a reporter for detecting TRAPed cells. My question is, is there around any fluorescent protein having faster (in the range of hours to 1 day in neurons in vivo) expression times?

Thanks in advance!

Sergio