Hemizygous transgenic mice are viable, fertile, normal in size and do not display any behavioral abnormalities. Mice homozygous for this transgene may not be viable. When these transgenic mice are bred with mice expressing the tetracycline-controlled transactivator protein (tTA) under the regulation of a tissue-specific promoter, expression of the CDK5R1/GFP fusion protein in the appropriate tissue of the bitransgenic offspring can be regulated by doxycycline administration. These mice may be useful in studies of Alzheimer's disease and other neurodegenerative tauopathies, amyotrophic lateral sclerosis (ALS), Niemann Pick Type C (NPC) disease, and Parkinson's disease. The Jackson Laboratory 2024, used with permission.