Generation and screening of transgenic mice with neuronal labeling controlled by Thy1 regulatory elements

Major progress has been made using in vivo imaging in mice to study mammalian nervous system development, plasticity, and disease. This progress has depended in part on the wide availability of twophoton microscopy, which is capable of penetrating deep into scattering tissue. Equally important, however, is the generation of suitable transgenic mouse models, which provide a "Golgi staining"-like labeling of neurons that is sparse and bright enough for in vivo imaging. Particularly prominent among such transgenic mice are the so-called Thy1-XFP mice (in which XFP stands for any fluorescent protein) that are used in numerous studies, especially to visualize spine plasticity in the cortex and remodeling in peripheral synapses. New generations of Thy1-XFP mice are now being generated at a high rate, and these have allowed previously difficult experiments to become feasible. Moreover, with easy access to core facilities or commercial providers of pronuclear injections, generating simple Thy1 transgenic mice is now a possibility even for small laboratories. In this introduction, we discuss the Thy1 regulatory elements used to generate transgenic lines with neuronal labeling. We provide a brief overview of currently available Thy1 transgenic mice, including lines labeling neuronal organelles or reporting neuronal function.