What have we learned from TTR-Null mice: novel functions for TTR?

Abstract

Ablation of the gene encoding for transthyretin (TTR) in mice showedthat, in the adult, TTR is not necessary for thyroid hormone and vitamin A deliveryto tissues despite the decreased levels of serum thyroxine and vitamin A. Surpris-ingly, the absence of TTR resulted in behavioral alterations. Specifically, TTR-nullmice display decreased signs of depressive-like behavior, increased exploratoryactivity, and impaired spatial learning, which may have implications in disorderssuch as Alzheimer’s disease. The present chapter discusses the lines of evidenceimplicating TTR in behavior, and whether these are directly or indirectly related towell described or novel TTR functions.