Assay Systems and Models e.g., Knock-out Mice

Crucial to the processes of establishing the safety, efficacy, and mode of action of a drug is the availability and choice of appropriate and validated models for the compound, procedure, test, device, theory, or therapy under investigation. 

Pathogenic effects may be caused by mutant mRNA. In the case of myotonic dystrophy (MD, prevalence I in 7400 live births), is the most common form of muscular dystrophy in adult humans and results from the expansion of a CTG repeat in the 3 untranslated region of the DMPK gene. The mutant DMPK mRNA contains an expanded CUG repeat and is retained in the nucleus. An untranslated CUG repeat was expressed in an unrelated mRNA 

Since both hypermutation and switching are abolished by AID deficiency, AID-directed mRNA editing could be required for these processes. Alternatively, AID-directed editing might occur while the immunoglobulin transcripts are still attached to their genomic template. 

AID may therefore turn out to be an attractive drug target in the therapeutic modulation of antibody-dependent autoimmune diseases. °  

Another example of utilizing the mouse system for elucidation of cellular and organismal phenomena is demonstrated in studies of bone formation, resorption and remodehng processes. 

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