Tg(Thy1-COP4/EYFP)18Gfng

This transgene gives rise to a fusion protein composed of the first 315 amino acids of the light-activated, non-specific ion channel chlamyopsin 4 (COP4), also known as channelopsin 2 (CHOP2) and as channelrhodopsin 2 (ChR2), from the green alga Chlamydomonas reinhardtii joined to enhanced yellow fluorescent protein. The chimeric cDNA has replaced the Thy1 coding sequence and its associated introns, which contain sequences directing expression in non-neuronal cell types. The vector contains the entire Thy1 gene (including the essential promoter and neuron-specific upstream regulatory sequences, 3' polyA signal sequences and neuronal-specific expression signal containing introns) with the coding region removed (from the ATG in exon 2 to the end in exon 4, including intervening introns 2 and 3). Immunohistochemical analysis shows that mice with this transgene express the chimeric protein in neurons of several brain regions, including various nuclei of the brainstem, midbrain and thalamus; mossy fibers in the cerebellum; CA1 and CA2 pyramidal neurons of the hippocampus; and strongly in layer 5 cortical neurons. In the olfactory system, mice of this line express COP4/EYFP on membranes of the majority of mitral cells and in the neuropil of the inner plexiform layer of the olfactory bulb, where colocalization with the 5-H2A receptor, but not with GAD67, calbindin or PAX6, demonstrates that expression is specific to mitral cells. (J:122790, J:123609, J:123610)