What is the best reporter for both in vivo and in vitro optical imaging?

To date, the most sensitive reporter for deep tissue in vivo optical imaging is Firefly luciferase.  However, the signal is difficult to image under a microscope and luciferase is poorly immunogenic, thus not a good candidate for IHC.  For in vitro imaging, most microscopes and flow cytometers are set up with GFP filters and excitation sources.  If you need to accomodate both in vitro and in vivo optical imaging, you may want to consider using a dual reporter such as dual or even tri-fusion reprter genes (Firefly luciferase, GFP, sr39TK (PET).  Keep in mind that it is recommended to put firefly luciferase "first" in the seuqence for highest expression and therefore highest sensitiviity for deep tissue optical imaging.  Optimized linkers such as "IRES" variant are published.

excellent references are:

Kim et al., 2004 - Multimodality imaging of lymphocytic migration using lentiviral-based transduction of a tri-fusion reporter gene. Mol Im Biol.

Ray et al., 2007 - Construction and validation of improved triple fusion reporter gene vectors for molecular imaging of living subjects. Can Res

Links to Reporter Reagent Resources