Identification of mRNAs under translational control by Fhit using polysome gradient analysis

Fhit is a tumor suppressor/genomic protective protein that is lost in more than 50% of cancers but the mechanism by which it works is unknown. Unlike most tumor suppressors Fhit is a cytoplasmic protein with no known interacting partners. A previous study found that Fhit regulates the translation of thymidine kinase 1 (TK1) mRNA into protein, with greater TK1 translation in Fhit-positive versus Fhit-negative cells. Increased TK1 translation was dependent on the ability of Fhit to degrade small RNA fragments termed nucleoside 5',5'-triphosphates. The goal of this study was to identify mRNAs whose translation is regulated by Fhit, and use this information to identify the proteins that are responsible for its tumor suppressor/genome protective effects.