Provided herein are mutant reverse tetracycline transactivator (rtTA) proteins and engineered nucleic acids (e.g., viral vectors, including lentiviral vectors, adenoviral vectors, AAV vectors, herpes viral vectors, and retroviral vectors, and non-viral vectors, including RNA and plasmid DNA) that encode a mutant rtTA that are useful, for example, in regulating gene expression, inducing cellular reprogramming, tissue repair, tissue regeneration, organ regeneration, reversing aging, treating a disease (e.g., acute injuries, neurodegenerative disease, chronic diseases, proliferative diseases, cardiovascular diseases, genetic diseases, inflammatory diseases, autoimmunue diseases, neurological diseases, hematological diseases, painful conditions, psychiatric disorders, metabolic disorders, cancers, aging, age-related diseases, and diseases affecting any tissue in a subject), or any combination thereof. Also provided herein are recombinant viruses comprising the engineered nucleic acids and methods of regulating (e.g., inhibiting or inducing) cellular reprogramming, tissue repair, tissue regeneration, or any combination thereof.